People have been predicting doom for Twitter for whole 2 years. Some left (mostly for Threads) but most stayed. Twitter is doing fine. Its biggest threat is probably substack and bluesky, but not fedi, and definitely not nostr. 

Similarly bitcoin is absolutely no threat to USD or even EUR (or any real money one can use to buy food and pay bills). 

It's bizarre to see so many clever people sniffing their own farts believing that "centralized platforms will be destroyed by decentralized magic".