I would highly contest this because conversely there are a series of victories by the Allies in the War of the Second Coalition that the argument is... Lackluster at best. However first we must understand pre Revolutionary Warfare, which I call dynastic warfare, how it came to be and why it was effective and then discuss why France was successful and unsuccessful for these fifteen years. Conversely we will also discuss why France stopped being as effective in 1809 onward.

Dynastic Warfare has its roots in a reaction against the Thirty Years War. I would suggest you speak to /u/itsalrightwithme or /u/waritter for greater detail about how war was raged. However the wars were seen as excessive and destructive by most major powers and there was a conscious effort to move away from that due to the cost, both in respect to economic cost and social cost. As such, there would be a movement of keeping battles away from civilian populations and keep the burden off the people, something focused on by France and Britain coming into the mid to late 17th century. As a result, the Nation-State takes up the cost of the military to ensure that it is within the nations interests and is loyal to the nation.

Most important to the dynastic system is that of the Crown holding and using the loyalty of the nobility for the State. This starts in different ways for different nations but for France, it's a result of two Civil Wars that are often rolled into one thing, the Fronde. In an effort to take away power from the Crown, the nobility of France and the parliament (think more Supreme Court than legislative body) fight to for feudal privlages (think states rights). They eventually lose due to political and social manipulation rather than conquest and thus the nobility find themselves loyal and under the Crown. In order to keep the nobility subservient and involved in the State structure, Louis XIV pushed his nobility into state offices or the military. As such the nobility would come to hold ranks in the military to ensure that they have a stake in the Nation.

And so, we have a tactical importance to the restricted model. With massive amounts of soldiers raised and personally funded by commanders or paid as mercenaries, this would cause problems for Nations, and so they would accept the burden of the cost by fielding the armies themselves. Noble officers would train these armies, being made of armies of no more than sixty thousand men but realistically thirty thousand men. They would fight in a way that would maximize their tactical limitation, the musket. In lines, they would train to fire and reload precisely; they would spend large amounts of time marching and preparing more mechanical movements; they would work not to be good fighters but to be a good machine. The armies of the early modern era were under the Enlightenment, they were to be a model of precise social engineering, a machine of state power.

Most nations would be similar to this, Prussia setting up one of the best armies of the Early Modern Era and Britain using a well trained but numerically small army that would use this linear, dynastic model well into the mid 19th century.

However, some saw this not as supremely perfect. The loss of the French during the Seven Years War was a humilation. Frederick the Great fought the Great army of Louis XIV, humiliating his grandson the King Louis XV as a leader. As such, the French were soul searching and it would be up to two men, the Comte du Gilbert and Gribeauval.

Gribeauval is important in that he changed French usage of artillery. Before, artillery was limited and slow, huge lumbering guns that many generals saw as a morale booster than a weapon of war. However Gribeauval would suggest using lighter and more accurate weapons in different ways, using their nobility to wreak havoc on the enemy and encourage the close use of artillery that saved Frederick the Great in the Seven Years War. Many resisted but by 1776, Louis XVI came to agree with Gribeauval.

The other important figure is the Comte du Guibert whom effectively changed military tactics. As I mentioned early but didn't go into great detail, the soldiers at the time fought in line using linear tactics. They would all march in one line and fire at each other, the one that would break would become the Victor. However this would become difficult because it would encourage only the mechanical precision that was beat into soldiers rather than using finesse or skill in warfare. Guibert recognised this as contrary to French spirit and argued for maneuver based warfare focused on using movement through column formation and line only to fight the enemy. With an emphasis on movement, there is less emphasis on killing the enemy but rather killing their will to fight, a major component of Napoleonic Warfare,

These two men would have their tactical theory fall together in the Reglement du 1791, or a combination drill manual, tactical manual, and military theory text that was to inform all officers. It would be carried into battle by the numerous elected officers of the Revolution.

This is where warfare changes. Warfare moves away from being Enlightened and more towards the chaos of movement. Revolutionary armies were far from skilled and with an emphasis on movement, lack of skill was replaced with bravery and determination. This isn't to say that the Revolutionaries were always victorious, they would slow down in Germany and Italy in 1796 until a young Corsican general inspires his army with said quick movements and daring assaults.

Conversely it takes decades for enemies of France to reform, part of it was due to the nobility resisting the movement focus as something revolutionary or others simply being too old to even change. By 1809, many older officers would be replaced by daring and capable commanders like the Archduke Charles, Swarztenburg, and others that actively tried to reform their armies. They would reject the parade ground maneuvers and focus on fire in favor of defeating the enemies will to fight.

Conversely the French fell apart. Early Revolutionary victories were due to multiple people in multiple theatres, but by 1809, Napoleon would be the only commander who could lead. Through ego, he didn't teach his men how to command, least they replace him. He shoved others that he didn't like it weren't qualified into retirement. Worse, his well trained army had been fighting for far too long, they were being replaced by green soldiers that vouodnt be taught by dead officers. The officers were falling too often, bravery and determination were wanted in officers, so a junior or mid level general looking to rise would be daring and brave, getting themselves killed and creating a brain drain. Worse many NCOs with years of experience were joining the Imperial Guard, making the Brain Drain even worse. The French weakened themselves while the allies learned how to wage modern war.

It isn't so much that nobility held back the armies of the allies. They continued to employ armies officered by only the nobility. They wouldn't see a major change of meritocracy and would undo any reforms at the end of the Napoleonic Era. Simply, they changed their tactical and strategkcal mindsets, they changed to fight their enemy.

Sources:

Blundering to Glory by Owen Connelly

The Campaigns of Napoleon by David G. Chandler

Swords Around a Throne by John Elting

Engineering the Revolution by John Adler

The Age of Battles by Russell Weigley.

One other major reason that I haven't seen mentioned here is that the French introduction of the Levee en Masse allowed France to have large pools of manpower that allowed France to take casualties that other counties couldn't take. France lost multiple battles to the coalitions against it but was able to replace many of these armies because of mass conscription that had not become common-place in many other European societies yet and gave Revolutionary France a distinct advantage. This Levee en Masse would become what we now think of as conscription and would become adopted by all major European powers either during or after the Napoleonic Wars.