In the encryption wars it goes the other way. Encrypters get to make decrypters exert exponentially more effort for only polynomially more themselves, and the systems get stronger over time, not weaker. We've long since passed the point where handheld devices like cell phones can use encryption that would take resources in excess of the entire universe for the rest of time at the maximum theoretical computation rate to brute force. We don't always use that, and there may be (and probably are) weaknesses that can cut that down, but that's the direction this goes in over time, and I can't think of anything that has any chance of changing that dynamic. Even a proof of NP = P wouldn't do it (that only potentially nails certain forms of encryption used today, there are others that would still not be vulnerable), and if that's not enough....

I know all that, but you have to agree UEFI makes everybody put a lot of trust on a series of black boxes we cannot inspect. Even if we assume getting a set of signing keys requires more computing power than physically available, we cannot rely on it not being available through less compute-intensive ways.