I don't know about "most". For various reasons, I use a 2-year-old browser on a daily basis (alongside an up-to-date browser), and I routinely run into websites that are completely broken on the 2-year-old browser. Unrelated to outdatedness, I recently ran into a local government website that e-mailed me my password in plaintext upon account creation. I have no way of accurately quantifying whether "most" web developers fall into the competent or incompetent bucket, but regardless of which there are more of, there are a significant enough number of incompetent ones.
I think a very common browserlist target is "last 2 version, not dead, > 0.2%". So if you have a 2-year old browser you are probably dozens of versions behind and are very likely in that 2% of users which developers simply ignore.
Going back 2 versions, only ~50% of Chrome users are on v140 or newer. If you go back another 2 versions, that number increases to around ~66%. Going back another 2 versions only increases that to 68%, with no huge gains from each further 2 step jump. That you think your target gives you 98% coverage is concerning for the state of web developers, to say the least.
After checking further, almost 20% of Chrome users are on a 2+ year old version. If you handle that gracefully by polyfilling etc., fine. If you "simply ignore" and shut out 20% of users (or 50% of users per your own admission of support target), as I have encountered in the wild countless times, you are actively detrimental to your business and would probably be fired if the people in charge of your salary knew what you were doing, especially since these new browser features are very rarely mission-critical.
I was specifically referencing desktop Chrome, not including Chrome for Android, but other than that, if there are discrepancies, I'm not sure what the cause is.
The Timo Tijhof data is based on Wikipedia visits, and shouldn't be affected by adblockers.
Meanwhile, StatCounter is based on sites that use its analytics, and on users not using adblockers that might block it. The CanIUse table makes clear there's a long tail of outdated Chrome versions that each individually have tiny usage, but they seem to add up.
It's fascinating they're so wildly different. I'm inclined to think Wikipedia, being the #9 site on the web [1], is going to produce a more accurate distribution of users overall. I can't help but wonder if StatCounter is used by a ton of relatively low-traffic sites, and the long tail of outdated Chrome is actually headless Chrome crawlers, and so they make up a large proportion relative to actual user traffic? Since they're not pushed to update, the way consumers are. And especially with ad-blocking real users excluded too?
Anecdotally, in web development I just haven't seen users complain about sites not working in Chrome, where it turns out the culprit is outdated Chrome. In contrast to complaints about e.g. not working in Firefox, which happen all the time. Or where it breaks in Chrome but it turns out it's an extension interfering.
Note that the comma in browserlist queries are OR. So if any given browser version still has > 0.2% usage, it is included. This would include Chrome 109 which is three year old. Meaning developers with this browswerlist target would fail their static analysis / peer review (actually even a more reasonable > 0.5% still fails on Chrome 109) if they used a feature which Chrome 109 doesn’t support without graceful degradation or polyfill.
Furthermore the "baseline widely available" target (which IMO is a much better target and will probably become the recommendation pretty soon) includes versions of the popular browsers going back 30 months, meaning a competent team of web devs with a qualified QA process should not deliver software which won‘t work on your 2 year old browser.
I can‘t speak for the developers of the websites which break on your 2 year old browser... Maybe they don‘t have a good QA process. Or maybe you were visiting somebodies hobby project (personally I only target "baseline newly available" in my own hobby projects; as I am coding mostly for my own amusement). But I think it is a reasonable assumption that user tend to update their browsers every 30 months, and you won‘t loose too many customers if you occasionally brake things for the users which don’t.
