I don't know about the USA but here in The Netherlands things being said during elections certainly aren't set in stone. To name two examples: empty promises get made, and rhetoric gets used. Now I know the latter is true in USA even far more but I am not sure on the former.

Empty promises get made all the time. This isn't one of them. Facebook wouldn't survive a Warren administration, e.g.,—assuming that Margrethe Vestager leaves it intact.

I really do not think Warren is messing around. Now her actually reaching the presidency is far off and certainly not guaranteed.