Compulsory Gridanian Education

[Enkidoh]

Actually, even towards the player the Guilds are shown to be somewhat insular and exclusive - after all you're only allowed to join one right at the start (the guild of whatever class you start the game as), and that's only after you first register at the Adventurer's Guild and are directed there by the proprietor. Presumably it's all a matter of red tape - average people may want to try and join a guild, but unless they have that permission from the Adventurer's Guild, they're out of luck (presumably this is also the cause of the situation of the antagonist in that FATE you mentioned - it was probably bureaucracy that caused her to be refused entry into the Guilds she applied to).

And even then, you're not allowed to join any other Guild until you've actually shown promise in your initial profession (as in, done the first few quests for the Guild), and are given permission by the Guildmaster to do so. It seems to me to be a very rigid way of education, but not too unlike real world history where trade Guilds were notoriously close minded and had stringent recruitment and training protocols.