I believe that if revolutions keep happening, then some of those revolutions will be communist - and as long as capitalism remains incapable of resolving its own contradictions, revolutions will keep happening. It seems like this isn't the case because we are corrently in a lull period where no revolutions are happening, but the so-called "Pax Americana" cannot last forever.

Think of it this way: Liberalism took hundreds of years to replace monarchism. The first French Republic was a failure, and was replaced with a monarchy. In the same way, the Soviet Union was a failure, and was replaced with a collection of capitalist regimes. But America lived on, and maybe someday just as America is one of the worst liberal systems to live under as a result of being one of the oldest, perhaps in the 23rd century China will be one of the worst socialist systems to live under for the same reason.

Now, the big question that everybody else is posing is whether or not the planet will survive long enough for this process to play out, and I think it will. I think things will get progressively worse, many places will have world-historic humanitarian crises, but the system will adapt to new conditions, find new energy sources, find new exploitable populations, etc.

Ironically I think that climate catastrophes might give capitalist regimes a shot in the arm in the same way that war can - give the state a good reason to put the money of the wealthy to work, and generate a ton of economic movement but this time you're building sea walls instead of bombs. I dunno seems plausible on the surface to me at least.