[…] it also completely breaks CDNs like CloudFlare. CloudFlare can deliver static assets much faster and simpler than Moodle can. – Potentially faster, simpler and wrong. For example, theme SCSS can be customised, Moodle will then regenerate the cache and serve the change immediately, the CDN will serve the stale content.
As I see it Moodle has to walk the line between optimising content delivery and ensuring the right users get the right content in an LMS where there can be a lot of changes to data. If you look under the hood at how that's done you'll see a lot of work has gone into tuning performance.
But there can always be improvement. If you have specific examples of items which could be improved then please share them – there's a Hardware and Performance forum for discussion of performance issues – or add them to the Tracker.