Search market share is all about placement in the browser experience. The most is the browser share. If anyone remembers the browser wars and portal wars that’s what that was all about. Until chrome is dead and Google stops buying the front door on most other alternatives their search engine will dominate. Not because it’s better but because it’s the lowest energy configuration for accessing internet content.
Remember when Bing was integrated into chatGPT? Now I do about half my searches through Bing.
But, it is unclear whether there is room for advertising in chatGPT the way there is room for ads in search. But I suspect there will somehow be a way!