That’s more because it was a bet on the wrong horse. If you know how to install Firefox you probably know what search engine you are using and how to switch the default search engine.
Isn't installing Firefox the same as installing any other browser?
It's not the default browser on most devices. I think the parent comment is stating that if you're technical enough to install a 3rd party browser, you're technical enough to pick your own search engine. So people chose Firefox and chose away from Yahoo
I think Firefox users have now reduced to geeks and some 'real FOSS' enthusiasts etc. I still use Firefox as my primary browser, but I haven't seen any non-tech person installing it for a long time now. They all just search for Chrome and download, install that. So in today's times if someone's installing Firefox I'd say they'd mostly know their way around.