Regardless of whether you think all those components are necessary, there is still the question of whether the amount of space they require is justified; JavaScript is a high-level language, and in fact one of the higher-level ones in comparison to things like C/C++. 1KB of JS should be able to do far more than 1KB of C or even binary.

Thus, 100MB of JS is astoundingly huge. It's roughly the same size as all the binaries in a full install of Windows 95, with all its features and drivers.

In the spirit of https://prog21.dadgum.com/116.html perhaps we need a list of "Things an empty Rails app is smaller than".

It takes a ton of cycles out of development googling "can I use feature X in browser Y".

...or you could just avoid the trendchasing and use a minimal subset that you are sure will work everywhere, but that's a different discussion.