$15 a month is stupid - the game is long since dead...
$5 a month is reasonable, with the option to purchase all the vet perks we had at day one until the close, at a certain premium - whatever that might be.
Well you can't play it all if the game is dead, so $5/month seems excessive while it's dead. Also, the whole point to buying the IP and the i23 server image is to reboot the game using Unreal Engine to current graphics and gameplay capabilities and continue expanding and developing the game in a new engine. That would need to be funded with something more than dreams and unicorn farts. More likely is the game will come back with the same basic setup as before, and you can even continue playing for free if you don't mind the limitations.
If the game hadn't been shut down would you have demanded that subs be lowered to $5/month three years ago? Y'know, because it would be in a similar state anyway...
Edit: So the whole point would be to restart the game as it was at shutdown while working on the engine port, which has been in progress on a volunteer basis for a few years now, but would have official approval and actual funding if the purchase goes through.