I agree with the other users above, Diamond level will be quite high requirement for a VIP host. They may apply a certain amount of wager requirement to every user who has a VIP host, the wagering will be needed to continue with the host on the next month. Stake has already hired a good number of hosts, and there are also a good number of Platinum IV+ users who doesn't wager anything significant for a long time. They can reduce the load from the host by applying wagering requirements every month.
I've heard here that to keep a VIP Host they have to wager $50k per month (I forgot who said it) well, that means it's been implemented. What I said is not in the near future but maybe in the next 5-10 years who knows. For me it's not that important because I don't expect to have a VIP Host you know $50k would be a burden since I don't have a specific budget for gambling just rely on the sig campaign

VIP host should not be something to expect or to chase, take it just like other VIP benefits because all of these benefits is just a bonus of our gambling activity in Stake. I had a VIP host few years ago but I lost it after Stake changed the rule from Plat 1 to Plat 4. Some users with the same situation as me can keep the VIP host until now, maybe because they are actively gambling while I was not that active in Stake few years ago. I am currently Plat 3 but still far away to Plat 4 to get a VIP host back, I will not force myself to gamble/wager just for VIP host obviously. Anyway, as corrected by ahoybrause above, once a user get VIP host the minimum wager requirement is $50k but within 90days instead of 30days. Mathematically it is like $16,666 per month but I believe it is flexible which means that even if we do not wager at all in 2 consecutive months, we can wager the $50k in the 3rd month.