Howso?
Since he made those predictions renewables grew many times faster, and with a much shorter doubling time, than he had predicted. But even before that renewables were on an experience curve that would have rendered his predictions implausible.
By pointing out both the necessity of the transition and the historically slow pace of such transitions, Smil is raising the pressure on achieving such a transition rather than encouraging complaisance and/or excessive tolerance of the rate of change to date.
And despite the current pace of change, we're still far from goals with impacts of failure to move off fossil fuels ever more evident.