As far as i know PSG is far from having the biggest wages in the world. Even MU pays more in average wages.
MU is known for spending something like 50% of their turnover compared to Barça 70/80+ %.
If they really want they can afford it.
And when i say, de Ligt stature, i don't mean salary wise. They are hot on talent like Sancho or Felix that will cost a lot on fee but not necessarily on wages.
The problem with that is Man Utd are so far behind with having a quality squad. They literally need to spend around £500m just to compete..... and even that's going to take years. Their squad is awful.
Besides, there isn't much talent out there that's going to be cheap. Also, do the top players want to go to a club that's not even in the Champs League? Yeah... I'm sure Man Utd can spend a lot money on wages and so on. But they still need to watch what they spend. And are they actually willing to trust Solskjær who struggled like hell in the last 2 months of the season with a big budget? I doubt they will.