Why can 15 year-old DVD players show the latest released movies perfectly, but DVD ripping software sometimes can't?

I get that the MPAA is constantly working to improve the copy-protection technology of their movies. And I can see it’s a game of cat and mouse with the de-CSS software that’s available.

What I don’t get is how a DVD player purchased in 1996 is able to play the latest Disney (or Sony or WB, etc.) release without a hitch but my PC-based ripping software sometimes cannot (don’t know until I try). Hell, even the basic DVD player software on my PC shows the movie fine.

What is it about ripping software that’s so fundamentally different than the dedicated player?