I'd say no on both counts. I don't think people opting for their oversized wear is a new phenomenon, they always have, with this generally coming down to comfort and practicality. While I love my cute little dresses and skirts, if the weather is bad or if I'm running late, it's easier to chuck on a big jumper. When deadline season hits and I'm already overwhelmed, I'd much rather be in baggier trousers that don't trigger my sensory issues, like jeans do for a lot of people.
This also becomes the reason I don't think of oversized as a 'trend'. I don't think we'll see oversized dominating the runways, or breaking into the high fashion category - perhaps part of the appeal comes from the low stakes of it all - if I'm wearing my baggiest clothes you'll know I've put my lowest effort into the fit that day.
All in all, the allure of the oversized clothing category stems from its comfort, inclusivity, even versatility - so no, I don't think of oversized as a trend, and certainly not a phenomenon that'll die out anytime soon. For me personally, oversized is perfect when I just need a few days off serving my meticulously curated fits, and I'm sure many feel the same.