Were you sober when you came up with that? You've got it back to front, the amount of fiat coming into markets dictates how much fiat miners have available to pay their running costs, mining adjusts its overheads to match it. 40% or 100% makes no difference to how much fiat is coming into markets, it only effects what percentage of that fiat is spent on mining running costs.
Doesn't matter. You're not understanding a simple accounting equation and focusing on a lot of hand waving nonsense about running costs and mining dynamics that have no relevance to this in accounting terms. They're common to all mined coins.
To see this, ditch all your mining metaphors (because that's all they are). Get them right out of your head and consider the blockchain as a decentralised market where bidders bid for the new supply. That is the more informative and accurate economic metaphor because anyone who wants. If you issue some of that supply with a zero price into the market, it's not going to do anything but corrode the viability of the rest of the market - obviously.
In that context, masternodes are no different from non-dash holders. You might as well give the reward to a non-masternode holder for all the good it's doing the network, but the fact that it's issued at 100% profit for the node holder is disastrous for Dash as an investment asset because that profit HAS to come out of marketcap. There is no other source for it.
Remember I'm talking about the
nodecount equilibrium condition. I realise that masternode rewards provide an incentive initially for people to invest in a node, but once the nodecount as a whole reaches a stable level and there's no net nodecount growth, we're no different from Bitcoin where most of the supply is also held in wallets.