I think it is highly possible that the closer they get to the answer the more exponential the problems become, similar to reaching the speed of light.
Something that always keeps coming back to me is the phrase "There ain't no such thing as a free lunch".
Exactly. And it's not just a smart-sounding phrase—it was proven mathematically in 1995 by Wolpert & Macready. I remember referring to their paper when I was doing research back in the late 90s.
Santa Fe Institute — No Free Lunch Theorems for SearchThe full paper in PDF format can be found in the above link.