One of the simple reasons: because they can. One of the biggest reasons a lot of people missed about the early days of WoW and the record high subscriber count

One of the simple reasons: because they can. One of the biggest reasons a lot of people missed about the early days of WoW and the record high subscriber counts, too. 15 million people worldwide played World of Warcraft, because 15 million people worldwide were able to install and competently run World of Warcraft. It originally ran on a Pentium III or a Mac G3. That opened up the amount of people who could even come to the table and consider ponying up a subscription fee. So when looking back on Ultima, it would literally run on anything. It is a relic approaching the opposite end of the spectrum, from a digital preservation standpoint it's becoming more difficult to run it on things. But you still can. So people do. That's really step one, in my opinion.