Because anything that impacts availability will result in piracy.
If users can't or won't be able to afford it, they will pirate it. This cna be tempered with pricing strategies.
If it can't be purchased, people will pirate it (e.g. region locked games, even w/o localizations, or delayed releases by market) - pricing doesn't matter here - if users can't get it, they will just pirate it, sometimes especially because they know it's going to be released later, and that decision by the studio has made them feel second class.
If it's no longer available (abandonware, game developers that have gone out of business, etc) then people will pirate it. There are lots of platforms that are thriving on nostalgia right now because people want to pay for supported, working stuff. (For example, the resurgence of the Baldur's Gate and related games updates)
Take a look at any $streaming_service threads and you will see that anything that interferes with streaming service catalogs or pricing will yield shouts of "Arr" and people clearly stating they will pirate shows or use gray market streaming sites.
It's anecdotal but I suspect that most folks on this site are more comfortable with pirating movies or music, but often draw the line at video games because it is easier to relate to the development work done to make video games (even though modern blockbusters movies often have a lot of software development associated with them as well).