there are characteristics of natural monopolies, network effects, etc, where the huge tech institutions at least seem close enough that 'build a competitor' won't ameliorate the issues with them that crop up (as it hasn't in the past), too much power and influence concentrated with little oversight. Perhaps clearing up the publisher/platform legal ambiguities help promote competition but I'm not willing to say "the market will handle it" projecting into the future.

Here's an oped from a cofounder of FB who thinks it's already gone too far and competition won't fix it, I can't have too strong opinion other than it's not clear cut they should be let alone