why not he just raced 5 days in two months he is racing so low
More than the effort, fatigue, challenge, competition or even the confidence boost of winning all three GTs, I think it’s simply about the patience/motivation, or lack of it, to put up with the whole grind: stages, training, team routine and race life for 3×3 weeks.
In the current context, he knows he’ll win anyway. PR, monuments, worlds, one day races or even a short stage race give him more of a kick: go there, win, come back with another title without the daily boredom of the GT routine.