Have a look at his times on any climbs raced by the very top GC guys. You’ll see he is a fair way down, even when winning a stage. Margins of 2 to 4mins, depending on climb length.
Over a tour, he’d hemorrhage 12 to 20mins over the various mountain top finishes. He simply can’t do the 6.2+w/kg for 40mins, required to win grand tours.
I highly doubt he’d actually be able to safely lose the 7 or so kgs he’d need to, to become a true GC threat. He has a strong muscular frame, for a cyclist.
More importantly, please just let Wout be Wout.
As spoken about in regards to MVDP, these two riders are incredible as they are. Why do people want them to be dull GC riders? I personally couldn’t care less about the GC. I love riders like these two and value their vast array of different wins in multiple disciplines higher than a grand tour team display.