I've been in this space pretty much throughout the whole period. Applets never took off as a serious option. They peaked briefly around 2000, then flash took over and by 2005 Ajax happened and JS took over.
As for build times, modern javascript is like having all of the disadvantages of a tedious build process without most of the advantages. You are spending the time, yet still don't have static type analysis and exclusion of whole categories of bugs. The reality is that, mostly for political reasons, javascript was the only thing that ran in a browser and after particularly MS (but certainly not them alone) ran into trouble with security issues, nobody really dared to do much else for a long time. Plugin APIs were deprecated, proprietary browser specifics were abandoned, etc.
So, what's happening now is a long over due correction where people compile to some heavily optimizable subset of js called wasm. As soon as that becomes commomplace the whole argument for javascript needs to be revisited, pretty much for the first time this century.
As for build times, modern javascript is like having all of the disadvantages of a tedious build process without most of the advantages. You are spending the time, yet still don't have static type analysis and exclusion of whole categories of bugs. The reality is that, mostly for political reasons, javascript was the only thing that ran in a browser and after particularly MS (but certainly not them alone) ran into trouble with security issues, nobody really dared to do much else for a long time. Plugin APIs were deprecated, proprietary browser specifics were abandoned, etc.
So, what's happening now is a long over due correction where people compile to some heavily optimizable subset of js called wasm. As soon as that becomes commomplace the whole argument for javascript needs to be revisited, pretty much for the first time this century.