PSP was one of those programs (along with Winamp) that are the hallmarks of the golden age of user experience for me. They had a lot of functionality but were very lean, a joy to use and reasonably priced. I miss the days when you didn't need a 100 MB (relatively speaking) package just to show a screen.
You also had to be an expert in multiple levels of the technology stack to build any program with cross platform support. Yes, packages were smaller, but developers had to do way more work and so applications were released less frequently. It would be very hard back then to make a cross platform program as a weekend project.
I'm pretty hopeful these days about Qt for Python and this build system: https://build-system.fman.io/
Unfortunately, it costs money even if your app is OSS, in some cases.