How did we learn that lesson when Microsoft did exactly what you're describing when they created XHR, and now almost every website uses it? It took 6 years for it to become standard, and I almost doubt it would have if it wasn't already in every browser by the time it did. My personal opinion is that this type of behavior boosts competition and helps innovation. If it's something clearly useful others will implement it or become obsolete. Waiting for a committee to standardize a feature before implementing it sounds like it would slow the web down to a halt. Mind you I already consider it to be painfully slow just looking at how many years it took to get 20-30 new functions into JS runtimes.
