Nowadays there is really no excuse for using ridiculously out of date stuff, decent spec refurbished PCs cost very little and there are modern alternatives to almost all old software except for maybe some very old and badly designed software used internally within companies. People are just scared of changing - They don't want to use a new piece of software that does the task they need much better than the old one because they may need to take a few hours to learn how to work it.
Take XP for example, it's coming up for 13 years old but people just won't leave it and move onto something new (probably because they are scared or something) - I mean, some people behave almost religiously about XP! I recently moved my granny onto Windows 7 from XP and like most others she didn't like the idea of change - Apart from having to point out that the start button no longer said start on it and that "I don't like the new solitaire" - I have not heard a single complaint or issue!
Well, few of us have penfriend life with very old computers.
I also have loads of vintage PCs from the early to mid 80s up until the early 90s - Doesn't mean I actually use them to get work done! They mostly sit around and are occasionally used for playing about with or running old games.