I disagree. Mobile performance is fine; modern smartphones and tablets provide more than enough power. It's enough power to be able to churn through huge photo

I disagree. Mobile performance is fine; modern smartphones and tablets provide more than enough power. It's enough power to be able to churn through huge photo libraries and power surprisingly capable video NLEs and multitrack DAWs; why should any website ever need more power than that? No, what we should pursuing much more fervently is browser engine optimization and more efficient JS. I've always been a strong supporter of baking more functionality found in commonly used JS libraries into JS itself (allowing aggressive optimization and reduction of number of libraries loaded) and while I may be wrong, I suspect that the web could benefit greatly from dependency sharing systems (if [lib] is already loaded from one source, don't try to load it again). And of course, nothing will have as much impact as thoughtfully written JS. There needs to be a big push in the web community to take responsibility for performance because expecting browser developers and increasing hardware power to magically make everything OK isn't a solution.