I admire his optimism, but I think it's irresponsible to sell it like he does.
Similarly, if we don't have bold predictions like these that we can actually measure within our lifetimes, we fall prey to fantasies that cannot be measured. Once this prediction fails miserably (I think) it helps many others to re-calibrate all their BS.
I'd argue that Kurzweil is selling precisely these kinds of fantasies that cannot be measured.
That we don't understand or can't define intelligence is a popular trope not grounded in reality. There are entire scientific and well-established fields that study digital and biological intelligence.
If we can't do that, I would argue that the computer has indeed become very intelligent, even if we can't define it. Just like beauty: we don't have a good mathematical model for what makes certain humans beautiful, but we all sure know it when we see it.
I admit, not the year 2000 and overly snarky, but people do marry computers nowadays. [0]
If we think it is what is(the computer controlled mask), we start to believe it really is what it is, a mind(controlling a mask).
Humans are capable of high degrees of auto-suggestion, up to a point where groups of people, and their dynamics, come into play, and some kind of group-thinking, a cult maybe for lack of a better term, takes over.
At this point all is believable, maybe not so far away. We may trick us into a false AI, not a GAI in any sense mind you, and get stuck with it, because most of us wanted it. And rest rest has been silenced already, that is very easy, as we all know already today.