It's not clear we have enough hardware. I've been trying to get a handle on the processing power needed for human level AI. If you take the naive approach and assume it's just a matter of getting models with the same number of parameters as the brain has synapses, our biggest models are about a million times too small. If you assume Moore's law will remain dead, then it may be a long while. Then again if modern deep learning is amenable to some sort of ASIC it could happen much quicker than one would expect, depending on how much investment is put into such things. And who knows how algorithmic advances will change things. If we ever get quantum computers, they're likely to be very useful in the design of conventional computers and materials technology in general, so another age of exponential advancement isn't out of the question.
It's very, very hard to be certain about these things.