For your second question, Matt claims that it's partly because WP engine disabled core features of WordPress. I can imagine a world where you are inundated with complaints that your software doesn't do X basic thing (because the top provider has disabled it) but ITS BEEN THERE THIS WHOLE FUCKING TIME TIME STOP COMPLAINING (put a smile on and explain calmly). You get my point. And then you snap.
No idea if that's what is in his mind but I have some sympathy for Matt. In principle. (This is me steelmanning Matt)
Heck even Jetpack, Automattics official plugin, recommends limiting revisions: https://jetpack.com/blog/wordpress-revisions/
Lastly, Wpengine never fully disabled post revisions, they just limited it to 2-3.
Not quite. https://wpengine.com/support/platform-settings/#Post_Revisio...
"Every WP Engine site has WordPress revisions disabled by default... Revisions can only be enabled by contacting Support... Support can help you enable 3 revisions for your posts to start. Revisions should not exceed 5."