First of all, the vast majority of devs do NOT stay "up to date." Most know one language or even just one platform... i.e. "WordPress developer" or "Oracle admin". Secondly, how do you think YOU hear about new technologies... usually due to marketing. Did React just come out of nowhere? No, Facebook marketed it relentlessly. Did people discover Kotlin on their own? No, JetBrains and Google hit people over the head with it. Etc, etc
Is it really the case that Facebook marketed heavily React? Why? What do they gain from it? Real question, or not like react was an entry point to their API?
It was fairly obvious when it was an up and coming thing. They sent out engineers to talk about it, you had these articles popping up about it more or less out of nowhere, etc. If you weren't there (which I'm guessing you're not, otherwise why would you ask), it is hard to imagine. Perhaps it makes more sense when you consider how normal "advertorials" are now.
