This will significantly impact (quite possibly kill) Startpage and Ecosia, who are effectively white-label Google, right?

What alternatives are there besides Bing? Is it really so hard that it’s not considered worth doing? Some of the AI companies (Perplexity, Anthropic) seem to have managed to get their own indexing up and running.

Excuse the self-promotion but Mojeek offers a web search API (>9 billion pages): https://www.mojeek.com/services/search/web-search-api/