Not really, actually, language change isn't really held back that well by institutions. Chances are that French just hasn't undergone that much change lately. I know, for instance, the Real Academia Española was formed in 1713 in Spain, modeled after L'Académie. But the thing is, Spanish texts older than that are still easy to read. Cervantes' well known text, Don Quixote, was published in 1605, and is completely legible, barring a couple of spelling changes (the main character's name is now "Don Quijote", but in an example of how well it has aged, the change from 'x' to 'j' actually reflects a change in pronunciation yet anyone who reads the original Old Spanish text wouldn't even know the original pronunciation; today they are pronounced the same way). This is because Spanish already had a well-established literary tradition. The difficulty in reading Old English is due to a number of other historical events; mostly the Norman Invasion, as well as the Great Vowel Shift. In addition, many older texts are written in a runic script, not the Latin alphabet. If anything, the only observations possible are that Spanish orthography is almost entirely phonemic, and French is also phonemic to some degree (as I understand). English, on the other hand, maintains more morphemic spellings; ex. "signature" clearly originates from "sign", even if they sound very different.