That's why Chrome market share is so important for Google, and why they will stop other advertiser to use it, and adblockers too. Chrome is the advertising channel for Google... and the entry point for Google Ads
And when ad blockers get so much better on other browsers people can switch. Especially now that IE is Chromium based.
Also in the US and to a lesser extent other developed countries, the wealthier more lucrative users are using iOS. Google knows this. That’s why they pay Apple a reported 8-12 billion a year to be the default search engine for iOS.
Out of the major tech companies - Amazon, Apple, Microsoft, Facebook and Google.
Google is one of the least diversified and has been the least able to pivot over the past decade.