A "dumping" period where your business gains marketshare and undercuts competitors to drive them under is an essential part of establishing monopoly power.
Also strangely enough it's illegal if you're already a successful company and try to do it in a new vertical, but completely fine if you're a couple unknowns with a few hundred million of venture capital.
Ninety-nine percent of private equity profits come from taking strategies that are illegal with regulated, public companies and applying them to unregulated assets. And venture capital is a subset of private equity. Almost every conversation VCs have amongst themselves would be considered market manipulation if it pertained to an exchange-traded company, and of course the fact that it's all insider trading goes without saying. So no one should be surprised.
This is one of those things that sounds right, and I'm inclined to believe, but I've never read any in-depth discussion of it so I'm hesitant as it's sort of confirming my own bias without a ton of concrete evidence.
Dumping doesn't work unless there is customer lock-in. Many companies believe they have moats and find their moats have evaporated 2 years later.