I think the license lasts forever. You can use the version you bought (plus the upgrades promised at the time of purchase) forever. That's why the site continue

I think the license lasts forever. You can use the version you bought (plus the upgrades promised at the time of purchase) forever. That's why the site continues to host older downloads. If your right to use the software expired after some amount of time, then that would be closer to a subscription.