To be fair, Ray Kurzweil has been the loudest voice in this space, and he's been pretty consistent on 2045 since the publication of his book almost 20 years ago[1].
He just had to pick a year where he would have a very good chance of not being alive.
Per that summary, we were supposed to have $1000 computers that could simulate your mind by the start of this decade along with brain scanning by this point in the decade. I guess if it is truly an exponential or hyperbolic growth rate, the singularity could catch up to his predicted date.