That's your version.
But now let's think that the mine bosses have bought the land and they know that if they are not profitable for the miners, nobody will exploit the mine and it will be forgotten and nobody will win in the long term.
What mine managers should do is not sell their ounces of gold below the lowest cost of production.
If for example the miner who obtains the lowest gold spends 1500 dollars per ounce, no ounce should be sold below that price.
This analogy doesn't describe blockchain mining. You're thinking of earth mining which isn't the same in economic terms and gold mining can't be used as an accurate archetype. In earth mining, the cost of production does not depend on the number of miners. The cost of extraction is fixed and depends on things like how deep in the ground the target mineral is, how sparse or dense it manifests etc.
Blockchain "mining" is different. It's a decentralised
market pure and simple and therefore DOES depend on the number of market participants (which are unfortunately referred to a "miners"). So the price in that (primary) market responds to demand for the next block. Much of that demand originates in secondary markets (exchanges) and finds its way into the primary market via the brokering function of the miner. So the capital flow looks like this:
Exchange Buyer --> $1000 --> Miner --> $1000 --> Increase in difficulty (and therefore price)
But for masternodes, that capital that enteres the exchange never reaches the blockchain and is not available for raising the price. Instead it goes onto the masternode's balance sheet and is lost to the Dash ecosystem completely:
Exchange Buyer --> $1000 --> Masternode --> $1000 --> Growth in MN balance sheet. (No difficulty increase and therefore no primary price increase)
Even if the masternode does not sell as you propose there is still a deficity in primary demand caused by the masternode balance sheet capturing the capital that entered the exchange market instead of passing it on to the chain.