It's funny how webkit-based browsers account an increasingly large proportion of users, but there's no similar trend in JS engines.
The JS implementation space seems to be much more diverse, at least in browsers.
Over the last 15 years, ~50% of improvement in chess engines is due to smarter programming, not better hardware:
https://www.reddit.com/r/chess/comments/76cwz4/15_years_of_chess_engine_development/
What other domains are like this? Lossy audio/image compression is definitely better today. There must be others situations.
One crucial factor in Stockfish becoming a leading chess engine is its test framework.
Summary:
https://en.wikipedia.org/wiki/Stockfish_(chess)#Fishtest
Initial announcement:
https://www.talkchess.com/forum3/viewtopic.php?start=0&t=47885&topic_view=flat&sid=b5662f579ad4c7bea91668bb9d9723a4
Lots of engines have clever programmers, but a strong test technique gave it an extra edge!