If the world population devoted its resources to develop a single supercomputer to crack a single 256-bit key, using round numbers...

2²⁵⁶ possibilities / (

2³³ people (8B and some change)

× 2¹⁰ units/person (may be generous)

× 2⁹ checks/sec per unit (GHz range checkers)

× 2²⁵ seconds per year (round, only 6% off)

) = 2¹⁸⁹ years

Even if someone developed a method better than brute force, say halving the bits to 128, 2⁶¹ years is still heat-death of the universe