Pogacar rides a different calendar because he's more talented than other riders who win the races you mentioned.If I had Pog's talent I would be doing 2 big one week races every spring + 2 Grand Tours every year and retire with 180+ pro wins. Pogi likes the adrenaline of the classics and winning '' easy'' races is boring for him. I applaud him for that.
Lemmond won the Tour and was 30th in PR. Hinault needed several attempts.
The reason for his current calendar is his great talent.
It all comes down to physical strength.
If everything depended on strength, Lemmond wouldn't have finished 30th in the PR, and Vingegaard wouldn´t have poor results in Liège and Lombardy.
Pogacar went to Lombardy in poor shape in 2023, and it was enough for him to win.
He could win easy one-week races, but he wants to showcase his talent in races that are difficult for the riders competing in the TDF.