Is this because it is a SPA? I'm hesitant to ascribe blame but I have to confess I'm pretty bored of inexplicably heavy frontend code that takes an age to both arrive and execute. Bonkers stuff.
Yes, a 6MB (compressed) bundle is big. But it is not clear that the alternatives are better. The bundle would need to be split increasing complexity of building the application.
It is likely judged that splitting the bundle only has minimal positives compared to the negatives - which also align with my experiecne developing software for roughly the same target segment.
The things developers usually forget is that there are other stakeholders than the computer executing code - IMHO a lot of developers would benefit from developing a bit of business acumen.
This is exactly the type of business acumen that is missing.
This is exactly why developers need more business acumen.