In reply to Amber Hinds.

I think the point maybe more that core should protect users more from doing things that slow their site. Rather like core is trying to protect users from having to know html and CSS or going through the pain of selecting the most appropriate page / site builders. It is totally possible for core to optimize images on upload, minimise and combine html/css/javascript, have built in page caching processes etc. rather than leave non technical users having to test the best marketed optimization plugins when they discover their site runs slow.

Just putting the other side of the coin there.