Shouldn't the question be: why are users selecting Chromium/Chrome instead of other browsers? The only real contender is Safari, but from the numbers that seems to be mostly from iOS and iPadOS where Apple has their own, enforced, browser monopoly.
Security. Speed. No delays in PWA feature adoption.
Then why did most people stay in IE back in the day?
activeX and proprietary plugins
Also big enterprises and governments were reluctant to change their web browsers quickly, which kept the % of use high for IE for longer than it would have been for individual users only.