There should be a very large gap between "theoretically impossible" and "practical". If cutting the search space in half gets you from one to the other, there's probably been an error in definition.
A $32 million (1985 dollars) Cray 2 super computer could do 1.9GFlops.
You can now get over 50x that performance for less than a grand in a device that fits in your pocket. I bet those engineers didn't expect that in half a lifetime.
That's rather beside the point. If 63 bits is insecure, then 64 bits is also insecure. If I can brute force 63 bits in a week, I can brute force 64 bits in 2 weeks. If we are worried that 63 bits is a security issue, then the solution isn't increasing to 64 bits, it's increasing to 96 bits, or 128 bits.
Moore's law was described in 1965 and the experimental evidence lined up for well past the next two decades. If you handwave exactly what it means to "everything is 2x better every 1.5 years," we'd expect a factor of 2^(30 / 1.5) = 1 million by 2015, so having a factor of 100,000x in cost and having it fit in your pocket wasn't actually unexpected.
Certainly any cryptosystems designed in 1985 that wanted to encrypt data until today should have taken the most aggressive form of Moore's Law into account.
