Maybe, the problem with old reddit is that it's as much about the comments as it is the content. Comments are hard to advertise on. Where card style scrolling content is great for advertising. Scroll a couple cards with a 20-60 second engagement, look at an ad, scroll a little more. . ..

However, I don't see this as being a great way to farm content for language models, the content engagement tends to drop significantly with the endless scrolling so my guess is that it's a short term play to prove they can sell ads before the IPO.