Your $10k MRR niche won't be "app that lets people hail taxis, and network of contract drivers." It'll be "reception table plan designer for wedding coordinators".

Google is not now, nor will they ever be having a meeting where they decide to allocate a few hundred engineers and marketers to crush that space.

There are tens of thousands of niches like this that will pay for teams of 1-3 people to live on the beach after a few years of work.