Windows didn't really manage the programs via the registry - there were hidden directories with configuration files for each user - there were 2 or 3 main directories and they held directories that were named the same name of the programs they were related to - the directory that held your bookmarks for firefox was called firefox (or Mozilla and in that there was a directory called firefox) etc.
If you actually had to fix and maintain your Windows box you probably remember having to clean after software that when uninstalled left a few directories and files behind and a few registry entries.
The registry was vast and clunky and littered with entries that were not needed and if you wanted to change some value there you had to pray before you touched the computer and then reboot and wait and check everything is okay.
If you dared install those nifty registry cleaning software you just gambled with your sanity.
Fixing Windows machines is annoying - why port a bad system to linux just because it's what you've known?
When moving to linux people don't install the WMP or Notepad - there are better programs that do just that and more.
The registry was a behemoth that needed a Ph.D to understand and patience and bravery if you dared change one bit.