you forgot the other variable of spez/elon causing another controversy that reignites the interest tho

Lemmy is a completely different thing. It is a grassroots movement of geeks motivated by an ideal. It has some chance of having enough people "fueling the fire" while it grows slowly and, also importantly, it does not need to grow like crazy to survive. This contrasts with threads, which is an attempt by a big tech company to capture mainstream audience. The mainstream has the attention span of 5 seconds, forms an opinion and never goes back. Either it is immediately fun or it is a flop. Threads had the best possible shot, riding on the enormous unpopularity of Musk and being able to piggy back on the huge user base of Instagram. They took the shot, it didn't work. The only way they can get a second shot is if another extraordinary event happens. I will admit that given the current tech leadership (and specifically Musk) this is not impossible, but otherwise I'm pretty confident in declaring Threads' stillbirth.