[jsalinas]

Bootstrap is a CSS framework and the flexbox layout is a CSS module, so you can't really compare them.

[BlackDeath3]

Do they not provide comparable functionality?

[RobertKerans]

It's analogous to asking if jQuery provides comparable functionality to JavaScript ES5 enumerables. It does, it's just a strange comparison given that the former is a library built on top of the latter language, using a different API due to the former predating the spec