Ok guys, let's joke about this for a second.

* The whole Bitcoin network will fail if a collision is found (because a needed hash algorithm will be broken).

* As the difficulty increases, there's more probability of collision, not only because of the increase of hashpower, but also because of the collision spectrum is smaller.

* Now imagine in far future that the target is for the first time < 64219. So the hash searched has the shape 0000000000000000000000000000000000FFFF, the probability of collision is ultra-high.

* Finally a collision is found and Bitcoin destroyed SHA256.

If you want to brute force SHA256, what's better than a monetary network with profit for every try?