Either you literally don't care about anything older than 4 years or you're being obtuse. That, or it will have to kill something you actually care about before you learn things the hard way that this is an actual problem.
You can, you can play the single player campaign over and over and over again for as long as your operating system supports it. Somehow you think that they have an obligation to keep their online PVP or coop servers running so you can play essentially a new scenario whenever you want (within the game limits) in near perpetuity for that initial 60 bucks you spent.
Good luck with that.