I definitely don't think AIs are supposed to be particularly tied to upper classes. As Momo noted, they barely have civil rights--Jeph's arguably undermining that with the introduction of a certain near-omnipotent AI aside.

But May isn't the exception. Momo is working class, Bubbles has gone between criminal class and working class, Pintsize and Winslow have a job that has no real-world analogue but I wouldn't map it to anything higher-paying than a live-in maid.