Ok, whatever, you seem intent on arguing about something that is at best tangential.
It's not "tangential" to make a distinction between ROI based on the invested capital and ROI based on the number of Dash you hold. From a store of value point of view, one is meaningful and the other is meaningless.
This is a very fundamental point and I'd like to stress it.
If you have a cake cut into 10 slices, and you then you make further cuts in it so that there are now 12 slices, then in terms of "slices" as your measure you've increased the size of the cake. But no self respecting customer would pay twice the amount for a cake that's sliced in 20 pieces as for one that's sliced in 10, so good luck in finding a market for such a business model.
That's what Dash is trying to do with masternode rewards and expressing "returns" as a ratio between the reward and the collateral. It's also the criteria that you're using to inform much of your argument and why they're leading you to false conclusions. You say you never mentioned "ROI" but you keep bringing up a figure of 6% without specifying what that is so I'm assuming you're alluding to the annual masternode reward as a ratio of collateral, promoted on Dash websites as "ROI" (which it isn't because the invested capital is dollars or some other currency, not Dash).
Now let's say collateral was reduced to 500 DASH. The masternode owner who previously had 5 masternodes, now has enough collateral to set up 10 masternodes but at twice the cost (using your mining analogy, doesn't that mean the difficulty just doubled?).
No, because "difficulty" is a metric that measures competition for the new supply. In mining, if the "difficulty" doubles it generally means you've managed to attract twice the size of your original market for the new supply. (i.e. there are twice as many people chasing new blocks as there were before). Hosting cost of a node has nothing to do with this. It just means that operating a node goes from being, say 97% profitable to 94% profitable.
I also would conjecture that this same owner would have an increased inclination to sell off at least one masternode in order to diversify or take profit. Also, someone new to DASH who was interested in masternodes before but couldn't afford/justify 1000 DASH, now has the ability to get in and set up one for the first time. I would think these scenarios are good for the DASH network. I also conjecture that masternode owners would be satisfied with a smaller number than 6%, as the collateral risk is reduced, which would in turn put upwards pressure on masternode count
I don't think this kind of headf* second guessing of people's psychology and trying to predict their behaviour is any substitute for a sound economic model. This kind of thinking seems to permeate the original "tokenomics" analysis as well. It's more sociology than economics and I think it's almost irrelevant because it requires so many assumptions that are impossible to verify.
For start, I've already said that I don't think a masternode should be considered as synomymous with a "person". It's a node, not a person. An artefact of the protocol. It can therefore be "owned" by 1 or more people just as any asset can, operated by the same of different people and any combination in between. What's relevant is the sheer amount of blockchain revenue that 1 node drains for doing almost zero-cost work.
It's enormous at half the supply. My point is that this makes the coin almost un-investible for new investors. The fact that nodes receive a "reward" is insignificant if that reward is wiped out because of capital loss on the collateral which brings me full circle to the "cake" analogy above.
I'm not suggesting that masternodes should be less profitable than they are now. I'm saying we need to give masternodes less cake slices and more cake weight.
