InfoWorld OpEd on Software Lifespans
The issue here is sure, that all vendors don't support all software for forever makes things hard on people wanting to rely on that old software. But there is a counterpoint - having vendors support that old software, even just in providing download links, encourages people to keep using software that is out of support and not ideal and potentially costs the vendors money either in lost sales or in support efforts.
Once software is past EOL, the vendors generally have a real incentive to make that software go away or to somewhat punish shops that want to keep using it forever. They don't make it timebomb or anything, but providing guaranteed downloads of it is not (or rarely is) in the interest of the vendors. They want getting old software to be hard or risky. Their customers could have maintained their own deployment backups presumably, so they aren't taking away from their abilities, just not catering to the situation.
Expecting or hoping that vendors will voluntarily hurt their own sales or bottom line in order to make customers who don't want to pay for support or buy current software versions have an easier time of it makes no sense. Sure, it would be handy and nice if they did, but that isn't how vendors make their money and it just isn't going to happen. We can't fix that dynamic but we can, one y one in our own shops, work to fix the situations that cause that to happen.