Free is to receive something in exchange for nothing, if I receive an interest for having my money deposited in an asset, that money is the risk that I assume, just as a miner risks his money in electricity and hardware.
This just isn't true. It's a fairy tale many investors seem to believe.
If you invest your money in equity, you'll get zip dividends unless that share capital is put to work. That work has to deliver "measurable" returns - i.e. measurable enough to appear on a set of books. So you won't get anything for your "risk taking" unless the company trades successfully. If the dividends you receive simply come from splitting the share capital into ever smaller pieces and delivering it back to you, then all that will happen is you'll end up with a lot of shares - all worth nothing. (Absent a nearby friendly central bank).
And you don't get interest on a bank account just from having your money in the bank. You get it because the bank re-invested it in some economic activity that generated a return where cash flowed between real people out in the real economy. So saying that putting up 1000 Dash to secure a node is "worth" something isn't enough. The market has to agree it's enough, otherwise it will just devalue your capital (which it's been steadily doing for the last 2 years).
So with that in mind, you do in fact receive your masternodes rewards for nothing: zip bookkeeping cost above your hosting costs. The 1000 Dash and hardware costs don't qualify as a "cost" since they're both capital assets. (Perhaps the depreciation on your hardware does, so if you want to depreciate a $3000 PC over a year against $5000 revenue then be my guest. You might have a case. But if Dash goes to $500 there are no associated scaled costs with that price increase. It all goes in tax and profits which makes for ever diminishing returns for new investors as a decreasing proportion of their investment goes into the network and an increasing proportion gets p*ssed away in masternode profits that they never see returned to them).
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P.S. In writing that post I may have just stumbled upon an explanation for why Dash bottomed around $60. That was just about margin parity territory for mining-masternodes. (If you take the example of writing off $3-$4k of hardware costs over a year for hosting).
Now, if we kept those margins at parity as the price rose, we might actually give it sustainable buoyancy instead of having it run into terminal velocity and slide back down again with a crash as the margins between the two reward groups got unsustainably out of sync. Stretched to snapping point.