Have you tried it recently? "Search for" gets me less 'deer in the headlights' looks than "google it", probably because these days most people are searching for things through apps instead of browser. Browsers are quietly becoming a niche technology with wide swaths of the population.
Browse the web as a normie would, without adblocker/etc extensions and other techy web saavy, and it should quickly become apparent why. Telling people to google something is like telling them to wade into a sewer.
Yeah as recently as this last week with tech peers, apparently "search for" came across as "look for this in sharepoint" not to search for it on the internet, but "google it" instantly was understood.
Browse the web as a normie would, without adblocker/etc extensions and other techy web saavy, and it should quickly become apparent why. Telling people to google something is like telling them to wade into a sewer.