The thing is you can't compare this to the Uijtdebroeks situation. When you want to get out of a contract, you need to buy out your contract. That's a bit more expensive when you earn 2 million a year, instead of 100k a year.Fair enough. But, as we've seen, it isn't easy to keep someone in a contract that they do not wish to honor these days. So they probably did some expected probability weighted value analysis and decided that, even if there is a chance that Roglic could go to Bora and beat Vingegaard in the Tour this year it still would make more sense to stand by Vingegaard. Letting Roglic go by no means indicates they "know" Roglic could never beat Vingegaard straight up.
If Roglic told them he was leaving no matter what (and was willing to buy out his contract at full price), then obviously my assumption of Visma knowing what he's capable of and letting him go, can also go into the bin. But honestly, i think my assumption is the more likely, but it's still merely an assumption.