IMO browser is a tool, just like operating system. The ultimate praise of a tool is "it works". For browser this means rendering every web page correctly, and for OS this means working on every hardware configuration correctly.

So if we already have a working tool, why do we want to spend the redundant work to invent more tools that solves the same problem, or to maintain the other tools so they are all standard-compliant?

Of course, it's a different story if the existing tool is monopolized by a commercial company. But Chrome is open sourced, and there is a committee steering the future Web standards.

So imo we don't need another Chrome, just like we don't need another Linux.