That's a lot of assumptions you are making there. Why "better projects" is the only metric considered here? Perhaps, OP utility in front end technologies is based on their learning. Or what's you reason to assume OP is dropping old tech "the moment something shinier comes around" and not after a reasonable period of exploration and trial?
Prototype.js was created in 2005, 10 years ago. Angular was released in 2009. React was released in 2013.
A lot of churn? Absolutely not. Someone staying current, perfecting their skills and knowledge? Good for them!
The HN trend of "hipster shaming" people trying new, sometimes esoteric technologies (even if it's only for the novelty factor!) is not conductive to constructive discussions and really has no place in the community named Hacker News.