theking2 :
It seems that Mozilla got scared of a faster, reliable, user friendly browser.
Edge is proprietary, and is thus much less reliable or user friendly than Chromium or Firefox just due to that fact. Significant amount of the reason why Chrome / Firefox are web standards compliant and even Edge is most assuredly not is because Microsoft has a few dozen developers working on their browser while Firefox and Chromium have hundreds of contributors from Google / Mozilla plus dozens of other companies and thousands of freelance contributors.
In the moment Microsoft wrote an ultra-optimized HTML rendering engine. Big whoop. It won't keep up with standards, and will likely not get updated often enough, and will probably still hold web standards back like IE has for two decades. It isn't a change in approach from Microsoft, just rebranding and putting a new paint job on the same old same old.
Who remembers IE11 when Windows 8 came out? It was beating Chrome and Firefox for all of a few weeks before the constant update cycle of the open browsers reclaimed the throne once they were able to observe Microsofts optimizations and either adopt them or similar mechanisms. Today IE11, the only Microsoft browser available on Windows 7 or 8, is now one of the slowest browsers on the market because they lack the raw manpower popular open source communities produce to constantly iterate on performance.