1. New Thing gets traction, 2. New Thing gets hailed as Next New Thing, 3. Everyone jumps on board and New Thing is The Only Thing you should be using, 4. New Thing Fatigue sets in as various things about New Thing aren't so great after all, 5. Everyone moves on to Next New Thing because maybe that really is the Next New Thing.
Rinse and repeat.
For those who have been in the game for as long as me (I'm not a proper dev but 30 years "doing web stuff" makes me an interested onlooker), it's a fairly tedious cycle to watch come and go over many iterations. It's one of the reasons I try and stick with boring old PHP + HTML + CSS + a sprinkling of JS for the stuff I do.
YMMV but the point is, it's everso tedious and unsettling to those involved trying to figure out what the next thing to focus on should be.