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

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.