CCGaDay Day 20: Game I'll still be playing in 20 years

The realistic answer here is Magic. Assuming they don't royally screw the pooch, they're the CCG equivalent of Dungeons & Dragons - the "default" game of it's genre. As an aside, I honestly think Magic is in better shape, because the market realities make it easier to accept buying new cards every couple months, whereas there's some serious fatigue around Yet Another Edition of D&D. But neither brand is going to disappear for very long.

Let's walk through the advantages:
First, they're owned by Hasbro, which means there are some seriously deep pockets behind them - beyond whatever war chests they've accumulated on their own. As long as the financials are good (or look to return to good), it's safe to assume that Hasbro will keep the line going. And considering that WotC/Hasbro owns their own card printing presses, that's a lot of infrastructure that's dedicated to making cards. Safe to say that Magic will be in the product line one way or the other.

Second, they are safe from the bane of all CCGs, licencing. So many CCGs have died simply because the owners of the source material decided that they might get a better deal elsewhere (or another company with deeper pockets lured them away). Decipher losing Star Wars is a well-known example, but Precedence Publishing can pretty much trace it's entire demise to licensing issues. Tomb Raider? Only allowed access to the video games, and then got shoved out when the movies launched. Babylon 5? WB withdrew all the licenses - and forced them to pulp outstanding inventory, prompting a firesale to get product out into the wild, thinking that Legends of the Rangers was going to be a big hit and allow them to renegotiate better rates. (Spoiler: the pilot/TV movie bombed horribly, but that was too late to save the game). But Magic isn't based on an external property, so no-one can tell them they can't make cards anymore. In fact, they've almost swung around to the opposite side, where Magic *is* a property that's licensed elsewhere (the video games, apparently a movie of some sort?). By owning their own rights, they can never be forced to stop making money.

Third, they've made the hard choices to keep the game sane, up to and including re-writing the entire rulebook for Sixth Edition, to changing card templates, set sizes, putting in rotation (and then changing *that* as need be). They may hit the day where "it's all been done" and there's no more cards to make, but I suspect by that point they could start repeating stuff and no-one would notice.

Now, that really only speaks to an existing game that will still be in print (and thus, "playable"). The lovely bit about tabletop games is that once you've bought them, they don't go away. So I fully expect that I'll still be digging out my Trek 1E, and my Lord of the Rings, and my Tomb Raider, and my dot-Hack, and all the other games through the years and enjoying them.