Linux kernel development survives because its biggest users develop it.

It's certainly possible for a browser to survive that way, but Konqueror doesn't seem to be terribly successful.

It's also worth thinking that many of those big users are also the very adtech companies people are hating on here, but for some reason it's fine to fund kernels and not web browsers with ads.

It would be interesting to know if Google engineers regularly commit kernel patches breaking Microsoft's Azure integration while pushing people to Google cloud.

It survives because GPL forces it to be performed in the open, in a cooperative manner. This is not the case with browsers.

Both Linux kernel and web browsers are arguably too huge now to be even maintained entirely by a single organization, let alone to be developed from scratch by one.

Linux being under GPL kinda forces cooperation between businesses for their business needs, if they are going to tweak Linux. With browsers are you under impression that you can just fork Chromium maintained by someone else and then just add your business value for you alone to reap.