They do, but Google reduced their utility. Ads from YouTube get through my uBlock Origin, and I see ads in my search results. This was a fairly recent development, as maybe a year ago I didn’t see any ads at all on Chrome. The day I got ads punched through my blockers, is the day I quit being lazy and migrated back to Firefox.

Google has no incentive to block ads when that’s part of their revenue stream, so they nerfed third party extension’s ability to actually work at intended.