Plenty of people play games through emulation that they didn't play when they were new. I certainly have done so. Whether that's something you've seen played by someone else, a famous classic you missed out on, or something you've played the later entries of and want to go back to.

The appeal of, for example, Nintendo's paid-for emulation services goes well beyond just stuff you personally played before, and the same applies to downloading roms.

Of course, even taking the nostalgia market alone, I don't know that having owned a game once creates a permanent right to play it free going forward, even in just a moral sense. How many of those people who had previously "experienced" a game sold their copies, or never owned one in the first place?