The reason that genuinely transformative AI may not happen in our lifetimes

Kurzweil explained it all decades ago.
Artificial Intelligence is almost completely a matter of brute force in the matter of its training and execution. Quantity over quality.
The problem is that the rate of improvement in processor size and speed may be too slow.
Imagine that fifteen years from now, AI will only be one thousand times better than today.
A thousand times better than what we have now should not be enough to make a qualitative difference.