It is commonly assumed that both France and the Germanic Kingdoms adopted Salic Law in the Early Middle Ages through their mutual origins from Merovingian and Carolingian rule. However, this is misleading. It is also assumed that Salic Law was specifically succession law, and while that was a big part of it, it was actually a much broader law code. It has since become shorthand for French Law excluding women from the succession. Because it’s common parlance, when I say ‘Salic Law’ below, I mean the French law specifically barring succession to the throne by women.

Let’s start with France, shall we?

The Capetian Kings of France ruled in an unbroken line, with the throne passing from father to son directly from Hugh Capet in 987 to 1316. Prior to this, Kings had been elected by the aristocratic elite after the separation of the Carolingian Empire. It had never been necessary to consider female rule during this time because Kings always had sons to follow them. It was not until the Death of Louis X in 1316 that this became an issue. At his death, Louis X left behind one daughter and a pregnant wife (who would later give birth to Jean I ‘the Posthumous’ who ruled for five days before his death). Louis did have brothers, but a brother had never succeeded a Capetian King before. Furthermore, the succession had been compromised by the Tour de Nesle Affair, where the wives of Louis X and his two living brothers were found guilty of adultery. So not only did they not have any sons between these three brothers, any children they did have were of questionable paternity by the standards of the day.

After the death of John I, a four year old girl named Johanna was left. The regent, Philip V, brother of Louis X and Johanna’s Uncle, has himself promptly crowned in Reims Cathedral. Robert Bartlett casts him in something of a Richard III role, taking power for himself. However, it is also likely that Philip V was able to get the support of the nobility because of their prejudice against female rule, and fears that a long regency would lead to political stability - and a long regency for a female minor, doubly so. Johanna did succeed her father to the Throne of Navarre, which had precedent for female rulers, notably her grandmother Joan I.

However, this raised another dilemma. If Johanna was to be excluded, Philip V and Charles IV would have to exclude their own daughters as well, and if women were to be excluded, and the throne passed to their closest male relative, the throne would pass to their nephew, Edward III of England, which was almost as unpalatable as a female minor ruler. So in order to prevent Edward’s accession, the final Capetians made the excuse that they were merely following the Salic Law laid down by Clovis, and that while women could not accede to the Throne of France, neither could succession pass through them. This lays the groundwork for the Hundred Years’ War, where Edward III and his heirs contested this by force.

Meanwhile, in the Holy Roman Empire, elective rule continued from the Carolingian Empire, all the way through the Hapsburgs in the 16th C. There had been attempts to establish hereditary dynasties, but none had been successful. Because of the culture of the time, the aristocracy would not have even considered a female candidate for rulership. And it doesn’t become too much of a problem until, as you say, Maria Theresa in the 18th C.

England after 1066 is different in that, like France, is has hereditary monarchy, but it has a succession crisis fairly quickly into the regime. Henry I, son of William the Conqueror, inherited the throne from his childless brother, William II. Henry went on to have a legitimate son and a daughter. However, his son died in the Wreck of the White Ship in 1120, leaving only Matilda, who was, at the time Holy Roman Empress. Henry I hastily remarried, trying to have a legitimate son so that there would not be a crisis over female succession, but he died in 1135 without leaving behind a legitimate male heir. He had dozens of illegitimate children, and it has been speculated that the English aristocracy may have considered giving the throne to one of his illegitimate sons, but evidence for this is scant. Henry I had his vassals swear fealty to Matilda on numerous occasions after officially declaring her his heir, but they broke with these promises and made her cousin, Stephen, King instead.

Stephen was not even the closest, legitimate, male relative of Henry I in 1135. He actually had elder brothers who may have also been considered for the throne, as well as other descendants through the daughters of William the Conqueror. Stephen was chosen largely because he was popular, and had the backing of the church through his brother, Henry, Bishop of Winchester (who was also named papal legate in charge of mediating the succession. Needless to say, he was not the most unbiased choice for the role). Matilda still had a lot of support in England, and a lot of opposition to her was actually down to distaste for her husband, Geoffrey V of Anjou because of cultural tensions between Normans and Angevins at the time. However, there was still a healthy dose of structural misogyny at work too. One of the biggest criticisms of Matilda was that she did not act in a traditionally feminine way. She was known to be temperamental, imperious, and unwilling to compromise - traits that had been acceptable when she was Empress, but not as Queen of England. She would be chased out of London having come very close to victory on account of her personality not melding with English expectation of rulership.

Matilda would, however, get the last laugh when Stephen was forced to compromise, making her son heir to England. The succession continued unbroken from 1152-1399, at which time Richard II was deposed by a cousin, who also claimed male-line descent from Edward III. England is also somewhat peculiar in this respect because, being most of an island, it was fairly easy to take control by force. In France, you might fight decades over a few territories, but only in England could you take the Kingdom in a single campaign. This definitely contributes to English culture being different than their continental counterparts. The identity of the monarch is much less dire when there is precedent for replacing them using military force, which would become the order of the day through most of the 15th C.

However, there are plenty of areas where there are female rulers who deserve more mileage. I believe that some of the focus on English female rulers is selection bias in the largely English-speaking academic world focusing on English-speaking subjects. For example, in the Iberian Kingdoms, you do see succession of women to thrones much more often, as well as in the Crusader States, but it is rarer to see casual histories dedicated to them because of the language barriers of resources and their accessibility.

I hope this has provided some insight on the unique contexts about the development of succession laws and customs in Western Europe. I’d love to see more added to this answer, specifically in reference to Iberian Kingdoms, the Crusader States and Eastern Europe. In summary, you might say that England differs from France and the HRE in that it does not adopt elective monarchy, but does not have a single, long-seated dynasty in power long enough before having a succession crisis in order to create some of the complex political problems that excluded female succession from countries like France. This, and it’s unique geography make it easier for women like Mary I and Elizabeth I to be accepted as rulers because of the long history of forceful succession wars.

Sources:

Robert Barlett’s Blood Royal. Specifically the section on the Exclusion of Female Rulership, which formed the basis of this answer.

David Carpenter’s The Struggle for Mastery a summary of English Medieval History that provides a lot of the context for this.