I wonder how many Edge users change their default browser from Bing to Google. I think the answer to that would probably make or break this case.
Default settings are very decisive in how most people set up their entire OS really. Very few people ever enter the settings app to customize things to their liking - most just assume any friction that the OS throws at them is just something the magical black box that does the computer things does and the only thing the user wants is to make it go away. Not understand it, just make it go away.
That's what a lot of Google's attempts to become your default {browser,search engine} is also aimed at - irritate a regular user just enough with the idea that if they accept it, all the nagging about that subject goes away. Most users don't fully understand their OS enough to get what decision they're making, so they end up with Google as their defaults.
(This is also super prevalent on Android - try denying say, the Youtube app, access to your notifications. The app will ask for notificaton permissions every single time. Google really wants access to your data and "no" isn't an acceptable answer to them. If this was a real human, you'd probably call that out as being creepy, but people tolerate it with Google for some reason.)
From that, I think it’s a safe bet Edge users don’t do that, either.
Maybe nobody uses the default anyway and they just type "google" into the bing bar before they do any searches.
If they can trick a user just once into going "okay fine", the Google installer runs and now Google's managing your defaults for everything else. Which is why obviously Microsoft tries so hard to prevent installers from taking over the default browser setting now.
I regularly encounter users who have actively malicious search providers and entire web browsers they do not know how they got. Tricking people into changing over is very much a thing, and actually how Sundar became as popular as he is.
People often forget that Sundar Pichai's entire claim to fame at Google was the Google Toolbar, which was snuck into Flash Player and Reader installs to hijack people's search provider. (The same bundled install trick was, of course, then adapted to growth hack Chrome's numbers as well.)
Vertical Tabs and Chromium without Chrome, what's not to like. Oh, and the ChatGPT sidebar.