Firstly, if the Germans had waited another ten years their economy would have collapsed. Their spending on re-armament was totally unsustainable and by 1938, Goering was warning Hitler that the re-armament program would have to end if something were not done. That something ended up being the invasion of Czechoslovakia, the seizure of their armament industries and their gold reserves providing an extension.
Even so, the French and the British knew that the German re-armament program would bankrupt the country before their own re-armament programs bankrupted themselves.
And of course the Soviets were re-arming with a vengeance
Time was not a commodity the Germans had to spare.
Secondly, the Wehrmacht was congenitally undesigned to stage a major amphibious operation against a major naval power.
After Norway, Germany's navy had been reduced to a rump and would be faced with what was at the time, the largest navy in the world.
They had no experience of amphibious operations, nor any specialist equipment to stage such an operation.
The Luftwaffe lacked fighters with enough range to penetrate much further than parts of the south coast, or the south east as far inland as (roughly) Amersham.
In short - To invade the UK, the Germans would have had to completely re-build their armed forces giving far more weight to the navy's surface fleets, building a fleet of landing craft, developing long range fighters and even then they would be staging an amphibious operation for the first time ever.
In reality it was not an option.
Sources:
Len Deighton - Fighter
Len Deighton - Blitzkreig
Williamson Murray - Luftwaffe - Strategy for Defeat
Chester Wilmott - The Struggle for Europe
To add to the answer from /u/jonewer - By the autumn of 1940, Hitler was convinced that Britain was no longer a threat, and in many respects he was correct. To justify his case for invading the Soviet Union, he made the argument that Churchill was just trying to hold on until Stalin could join the war against Germany. Therefore it was necessary to invade Russia in order to remove Britain's last hope and force them to negotiate.
Hitler did not foresee that Churchill was actually counting on the USA for support, nor that Britain would serve as a springboard for the liberation of Western Europe in 1944.
William Schirer - Rise & Fall of the Third Reich
Any source on "his generals advice to wait 10 years"?