In reply to Rick Gregory.

I agree that with enough developer horsepower all performance issues are solvable, however the number of site owners that can afford that level of time and expertise is fairly small compared to the total number of WordPress sites.

Furthermore, even for expert site admins, forking or patching plugins in order to tweak performance leaves you with a high maintenance burden and exposure to esoteric bugs. It would be nice to somehow minimise the performance overhead of all plugins so we can reduce that burden.

Ultimately, it would be best if WordPress could provide great performance out of the box, and good tools to see the impact of settings and plugins and content on performance. Rejecting all solutions that are necessary-but-not-sufficient is self-defeating, since poor performance comes from many areas. Cutting, say, 50kb from every site by using SustyWP as the base theme is not huge in percentage terms, but the web is so big that even a 1% performance improvement across the board is actually a gigantic amount of time, money and energy.