I’ve been on Linux for over a decade. Two years ago, I installed Okular (pdf reader) on my friend’s laptop. I was surprised to see it was a rather old Okular version. So the trouble goes further down. Maybe is just a lack of volunteers/ maintainers. Well, given Windows is paid, this would be just plain understaffing.
It’s worth mentioning that my current app store on Linux is flathub.org/setup (it’s distro agnostic). I highly recommend you explore WSL and Flatpak (flatpak is the underlying ‘packaging’ tech behind flathub). Here’s some good news from 2018, www.phoronix.com/news/Flatpak-Windows-Prototype