so, which Big Tech company do you think is going to shit the bed next and popularize its Fediverse/FOSS equivalent in the process?

I would love for something to replace YouTube, especially something in the Fediverse, but video unfortunately has much higher storage and bandwidth requirements, so it's hard to imagine that not being totally cost prohibitive at high levels of traffic, even if it's split across so many different servers. I'd love to be wrong on that, though.