> However, the only reason this is possible is because we have web standards that are independent of a single browser and vendor.

This is an important point. One thing that led to IE's downfall was its lack of standard compatibility. At the time, there were real web standards. Today, the "standard" seems to be whatever Chrome does. (Indeed, despite good standard compatibility, the pre-Chrome version of Edge suffered in terms of real-world compatibility, and that was an animating reason for the switch to Chromium: https://blogs.windows.com/windowsexperience/2018/12/06/micro...) So we are very differently positioned than we were when Firefox/Chrome overtook IE.