Do you remember GPT-2? It was a bizarre curiosity, but was nevertheless considered a huge advance in 2019. Practically useless, but interesting.

It grew, and three and a half years later we got GPT-4, which was exceptionally capable on release.

It grew still further, and three and a half years alter we got GPT-6. This is already more intelligent, more imaginative, more disciplined, and far more erudite than the vast majority of individual humans. If you have an intellectual skill -- if you are, say, a mathematician or a chemist -- GPT-6 also has that skill and is functionally your peer. And then it has many other skills that you do not possess.

Assume a steady rate of progress. In three and a half years, we're going to have something that is genuinely a general superintelligence, and we're probably going to see recursive self-improvement begin to kick in (though subject to physical constraints on compute, etc.)

All you have to do is assume that things don't plateau. They have not plateaued to date; if anything, progress appears to be accelerating, and people are starting to panic that there are no brakes on this thing...