I think your making a strong point here, that might not get the attention it deserves.
> asynchronous requests
Because we don't live in a world where one user loads one page and then loads the next one (and if they do we should be talking about how your not using cached static content).
If I can do the work in 20ms, and it takes 100ms with framework overhead what happens when these start stacking up?
Not only do those things impact the user they impact your server... every ms that it has to maintain that connection, do work is one more ms that it isn't doing work for someone else.
> asynchronous requests
Because we don't live in a world where one user loads one page and then loads the next one (and if they do we should be talking about how your not using cached static content).
If I can do the work in 20ms, and it takes 100ms with framework overhead what happens when these start stacking up?
Not only do those things impact the user they impact your server... every ms that it has to maintain that connection, do work is one more ms that it isn't doing work for someone else.