I don't think so; we are not even comparing apples to apples.
HTL is a markup language that runs server-side, while React is just a JavaScript framework that runs client-side. They have nothing to do with each other. On the other hand, replacing HTL with another technology would be a massive change that would impact several clients, and Adobe usually handles these types of scenarios carefully and in advance. So, I think you might have heard wrong. Please let us know if you have any source that we can check from
Esteban Bustamante