Having not run DOS/Windows since 1995 I haven't needed to. I can't imagine dealing with an OS without the kind of enormous and comprehensive software repository of Debian or pretty much any distro.
Right, but there’s a massive global economy of trillions dollars of software being bought every year. The people that run this site invest in companies that sell software. I just can’t comprehend how you wonder if buying software “is still a thing.”
Are these really the best possible version of the software? You can be an engineer and get away with using a hacked-together clone of some popular software program, but is the money really going to set you back farther than a good copy will set you forward?