[tracker1]

Static content generation, better optimizations and caching settings would go a long way... hell since many blogs are using third party comment systems, they should probably cache all requests for not logged in users for 5 minutes by default... it's up the application servers though.

Making any variance between logged in, and not logged in visitors limited to JS enhanced interactions would help for most systems too.

A current server can pretty easily hit C100K per cpu core... There have been test runs at over a million concurrent connections on a single large server instance. It's all on the application design... using an application that's a couple decades old as a common baseline is part of the problem... honestly, wordpress should just die already.