I think it's still less than the amount of effort the VS Code team has put in trying to make Electron work. The guys (I believe only two) at Sublime HQ have managed to create a cross platform UI that is efficient and works well.
Kinda depends if you want to find developers willing and able to reinvent a lot of things or not. If you can justify rebuilding a textbox or scrollbar (for example) then perhaps you can roll your own solution. Otherwise you look for libraries.
The web is rich with 3rd party support for a lot of things, so as a platform it's attractive. If you need to grow, you can be more confident it will have what you need. But with that also comes a lot of bloat, legacy and poor decisions too.
