If you think Platinum IV will increase every year then what you think could be right VIP Host will be more expensive may need Diamond Level to get VIP Host, they had already made this change a few years ago.
That would be crazy if the requirement to get a VIP host is changed to be at least Diamond level ($25M wager required), lets say the number of Plat IV is increased significantly every year, increase it to Plat V is already enough IMO as it is already doubled amount.
By the way, I think the best thing to do is not to increase the level requirement but Stake should hire more VIP host if the number of players who are eligible for VIP host is increased every year.
On one side, it can be something unfair for some people who are in the process of reaching the level as the minimum level to get VIP host but then there is a change made by Stake.