[iraldir]

Another point to support the same idea is data can be falacious.

For instance, you are making a pretty advanced 3D web app, and notice in your analytics that your userbase is only chrome and safari users.

An easy conclusion is to focus your testing on those two platforms, or maybe even drop support entirely for Firefox and Edge by using some webkit specific API.

A not so easy conclusion is the experience might be so bad or buggy on a non-webkit browser that anyone who tries the app in those just gives up on it.

The reasonable truth in this case? You should use standard browser distribution except if you're operating in a specific market, it might also be perfectly fine to drop non webkit browser if the ROI of developing them is not worth it for your goal etc. All of which does not need data but rather intuition and common sense.

[nicbou]

And a lot of privacy-friendly browsers don't show up in the stats by design.

[GeneralMayhem]

This is pretty standard survivorship bias - which is to say, a well-studied problem with a famous pithy example (bomber plane armor), that many people and organizations still somehow don't learn.

[jorticka]

It goes deeper.

People learn over time that complex web apps work badly in Firefox, because developers mostly test in Chrome.

So they don't even bother trying it in Firefox.

[nairboon]

Maybe. Or maybe Firefox users have sophisticated ads & tracker blocker, sometimes even UA spoofing. Then it really depends on your analytics method, if these users show up at all. You might have a lot of FF users, but analytics tells you otherwise.