They author thousands of open-source. Nobody would consider those 'products' (though feel free to play pedantic). And many would argue React did far more harm than good.
We would still have a framework of the week like we do today. There was a new framework weekly before React and there are frameworks of the week after React. React just gave us one more way of showing text on a screen.
In 2015 I was teaching that React was a lightweight library that simply did function state -> html, codebases were bug-free, snappy and easy to understand. And it was true compared to configuring jQuery listeners the unperformant way into a Rube Goldberg machine of cause and effect.
As someone working daily with React, I agree. And I wouldn’t consider it a Facebook product at all. The amount of work they offload to the community is substantial.
We would end up with some other (probably worse) JS frameworks instead, JQuery(shudder) was still big, Angular 1 was a glimpse of something but they went for Angular 2+ that changed everything, backbone js, ember js,etc.
Vue is probably the only outsider of that age that stayed even somewhat relevant (really by just doing what Angular 1 did but correctly), Angular seems to have kinda survived in some niches but other than that I haven't heard of the other similarly aged frameworks in a long while.