I feel after ten years or so, that is an unsurprising sentiment. Its also not a particularly new one- just look at 'now for something completely different' for all the times people have used this setting to springboard into totally unrelated settings. And certainly even what has been considered the 'default' setting has shifted with time somewhat (look at the composition of Jon's family, for example). That being said, the current setting has remained largely the default.
Both this and the fact that many characters are usually characterized by cliques or cliches seems to be a combination of familiarity, accessibility, and plain inertia. These characters are familiar and fit familiar archetypes, so authors feel more flexibility to do stuff with them. And because they are such simple character concepts (evil queen bee, bully jock, ornery goth), its something a lot of authors can understand and coordinate a consistent characterization with. Complex characters, while usually more engaging, are also harder for multiple people to comfortably portray. These factors, combined with the fact that this is just the default setting, make it most typical for things to circle around to Lakeside (or whatever name we assign the nebulous suburban town of You Are What You Wish).
Certainly some branches have gone so far they rewrite the whole setting (Iridescent Sun is probably the deepest rabbit hole there), while others try to characterize people as beyond their cliches. If you have a new idea for a new setting, just write a branch for it. People will jump on it as it strikes their interest.
This post was far longer than I expected, but that's my take on it.
