They wouldn't necessarily want to destroy the company, but it certainly helps them negotiate. Especially since there doesn't seem to be anything particularly special about Uber anymore. They did the hard work of breaking down bureaucracies and getting people used to the idea of non-professional drivers.

When Uber and Lyft left Austin, a bunch of companies popped up very quickly to fill the gap. It isn't clear to me what you are investing in if you were to buy Uber shares.