[Dalewyn]

There is (or at least was) some truth in computers getting worse over time.

File system fragmentation was a very significant problem when most people still used HDDs as their primary mass storage media. SSDs are far less affected by fragmentation because of much faster random access times, but HDDs and thus performance suffered.

The Windows Registry is an arcane secret not even Microsoft fully comprehends at this point, and it can get very messy if a user installs and uninstalls lots of programs frequently. This is, of course, a problem with uninstallers not uninstalling cleanly and not a problem with Windows or the users. With so much crap moving to Chrome online-software-as-a-service outfits, users aren't (un)installing as many programs as frequently anymore, but an unkempt Windows installation can definitely slow down over time.

Software in general also just gets more and more bloated as the moons pass. More bloated software means less efficient use of hardware, meaning less performance and more user grief over time.