Absolutely, local platform competitors can pop up, but the network effects of national platforms is powerful and their influence and actions damaging in the interim. We may just disagree on this, and that's to be expected. As previously stated, I believe more regulation is required, even if that puts national platforms out of business.
In the interim is fine. They also provide a vital role in establishing how online shopping for food should work. It's easy to copycat after, as is evidenced by even local providers being able to do it.
Food delivery has been around and profitable for generations. And there are several well-known apps in most markets. And just because a thing is illegal doesn't mean it doesn't happen.