I don't like this in principle, but in practice I actually don't care too much.
Primarily because when it comes to cheap TN panels of a few hundred £/$ I honestly think it's more or less a solved problem, you're not going to find a TN monitor by another company that magically blows the Asus brands out the water, the difference is fairly negligible these days, it's kind of like worrying about who makes your NIC, it's basically a solved problem.
Maybe in the PVA or IPS spaces where you're spending around 1k you might care a lot more. Asus clearly paid well for exclusivity, no one else cared to match their offer to Nvidia so they get to reap the rewards of their investment, their exclusivity is only really possible because no other monitor provider really gave Nvidia the incentive to work with them.
But yeah, in principle I disagree with exclusivity, I'd prefer it release in a competitive environment but then it's not for too long 3 quarters or so.