Earlier quoted context omitted.
My browser is not slow, for me starting and using a lot of desktop apps feels slower than browser apps to be honest.
Probably because your desktop apps are bloated, too. Any software that needs longer than zero point two seconds reacting to user action (this includes starting the program) should be improved upon.
Obviously starting the app is going to take longer, especially from cold, but if you ignore things like DNS resolution and download time then 200ms is more than enough for most things to get from 'downloaded' to 'interactive'.