Note that brute-forcing an exponential-time algorithm is not generally possible. If you have an algorithm with a runtime of 10^N, then after N=61 the runtime of the algorithm will be greater than the age of the universe expressed in the Planck Time. For a 2^N algorithm it'd take about N=202. If you're willing to talk in nanoseconds instead of Planck Times (chosen because our current understanding of physics breaks down at that scale), it's more like N=26 for the 10^N case.

Practically speaking, though, users of privacy coins are usually looking for plausible deniability rather than total untraceability. The legal standard for criminal cases is "beyond a reasonable doubt"; if there's even a 50% chance that you're just an innocent person caught up by circumstances, you'll have trouble convincing a jury of guilt.