You can't currently make an alternative browser in the same sense that you can make an alternative OS. An alternative browser would not use HTML, CSS, JavaScript. It would use something else in the same way that MacOS/iOS push ObjectiveC and Swift where as Android pushes Java/Kotlin and other OSes other languages and each OS as it's own UI API
Supporting the most use cases is where you get the compatibility from.
Being better than your competitors is where you get browser-exclusive functionality from.
If something (e.g. ActiveX, Java, Shockwave, Flash, some new CSS that's not standardized yet, a new feature on some top 500 website, ...) works in your browser, that's a win for both goals - and if it works only/best in your browser, that's also a win.
Monocultures can be toxic in part because the disincentives to adding lockin (e.g. losing users and other negative feedback sources) get weaker/less likely as one participant becomes more dominant.
I'm old enough to remember the fun with "works only/best in IE/Netscape/...", and Microsoft's old Embrace/Extend/Extinguish policies. While I do not have any reason to believe any of the parties involved in browser development would behave pathologically, history suggests that monopolies in any space tend to eventually become pathological.
(I work for Google, not on anything browser related, all opinions above are mine personally, etc.)
From what I've seen, yes absolutely, as long as it is Linux.
I feel like, if I wanted to, I could contribute to the linux kernel. All that I would need to do is submit pull requests, have it vetted, and gain reputation within that community.
Could you say that about any arbitrary pull request for chromium? Even if it was against googles interests to merge it?
Is your contention that I just fork it and compete with chromium with my PR integrated?
I don't view these projects as equivalent at all.
I would place myself squarely in the camp of those that don't see every browser using Chromium under the hood as a bad thing. It makes every company that has their own browser invested in improving together, for one thing. Also, compatibility across browsers will only get better if that is the case, which is also something that people tell horror stories about from the time when IE was king.
Let's just replace 'browser' with OS (ironically the similarities are becoming more with each passing day) above... would we still say the same? Is an OS monoculture good, regardless of whether it is inevitable? Have we forgotten the power that MS had with Windows during the 90s and early 2000s before Linux, MacOS and Android became viable alternatives?
Given that browsers are becoming the new OS and VM, we need competition in this space more than ever, going forward. Let's not accept Chrome/Google as the One Ring.