A standard is written and set in stone at least for 1-1.5 years. Official test suites are made.
Then, browsermakers make their stuff compliant.
APIs must support strict versioning. A user should not be bothered with "your browsers supports version 1 of method b, version 2 of method c, and does not support method d" it should either work with API version N or popup a big error message "API version N not supported, update your browser"
For the 3rd time, do you have an actual example of what's wrong?
In the 1.5 years of wait time you mention, the current process will have standardized and released features across all browsers. The web has changed and nobody wants to wait years discussing something. Compatibility is not a major issue because features are rapidly updated and there are compatibility tables that will automatically reference and even build your app for you with the proper polyfills and transpilations.
Sure, sometimes there are bugs and partial features, but this is rare and there's no evidence that W3C prevented this since implementations are not up to them.
However the W3C has definitely failed to make any progress with HTML/XHTML. They failed with SVG. They failed with DRM by completely ignoring the issues raised and causing the EFF to leave. So please state exactly what the W3C has done better and where they have added value because as far as I can tell, they are just wasting time every few months from the very people who are trying to move the web forward.
A standard is written and set in stone at least for 1-1.5 years. Official test suites are made.
Then, browsermakers make their stuff compliant.
APIs must support strict versioning. A user should not be bothered with "your browsers supports version 1 of method b, version 2 of method c, and does not support method d" it should either work with API version N or popup a big error message "API version N not supported, update your browser"