1. They're the incumbent with almost monopolistic market share. People aren't going to switch to a new product that's just roughly as good. It has to be way better.

2. Their search algorithm is straight up better than their next biggest competitor, Bing. The latter has tried for years to overtake google and failed.

3. They have copious amounts of user specific data across their products/services. That enables tailored AI responses.

You have a fair point about google propping up ad buyers. That is their Achilles heel.