Just make sure you download them and back them up yourself because they certainly can revoke your ability to download them from their servers, is what they are implying here.
Well yes, of course. They sell you an installer and it’s on you to download it. That the servers could be turned off at one point in the future because the company doesn’t have money any more should be clear. It’s on you to save the installer on your own hard drive, not the companies!
Sure, just like other brick and mortar stores can refuse to give you backups of a DVD you own.
As long as the installer works offline this is just as good. It’s up to you to store it in whichever format you prefer so that you don’t lose it - hard drive, thumb drive, DVD…
If you nuke your computers hard drive with the installers of your games, or you step on your blu rays with games and break them, then you lose access to them. As it’s always been, no matter the format?
Luckily there are some friendly people with eye patches and peglegs on the internet backing them up for you.
You might be surprised. Plenty of sites backing up whatever they can. Try archive.org and various abandonware sites.
In case of zombie apocalypse, your best friends will probably be a bicycle (to get away from the zombies in almost any terrain and road condition, not be without industrial fuel the next day, and be able to do needed repairs with rough tools and scraps that can be found), a hunting knife, and maybe a crossbow if you can find one (weapons that can be sharpened and reused, and crossbow allowing random joes to just make piercing sticks (again with scraps that can be found anywhere) that work like an arrow, again weapons that do not depend on industrial infrastructure that will not be available anymore). Games that need electricity would be extremely hard to use, it’s better to buy card decks that have multiple rule sets for different games to play, like french decks and tarot, maybe a tabletop set that also has multiple games.