Giro is only easy because Pogacar is probably the most talented rider ever. Giro-Tour will continue to be a very hard task despite being ridiculed by Pogacar.
In all fairness since Pantani only once the best GT rider tried it in his prime. That was Contador in 2011. And even then he had a very weak team and the hardest Giro in the recent memory. On top of that he crashed heavily in the Tour and his team was hardly better than the Giro.
In 2015 he was past his prime and the Giro was ridden very hard.
In 2018 Froome was past his prime and that Giro was also much harder.
Dumoulin got 2nd and 2nd with a weak teams and god awful tactics in that Giro.
I have no reason to believe that Vingegaard is incapable of doing it. Hell, with such an easy route 2008-2011 Contador and prime Froome could possibly do it as well.