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.