Game theory tells us how Dash's instamine may destroy its network effect.
A guy, let's name him "John", wants to accept payments or buy stuff privately with DRKs.
What John cares about is
a) The currency is anonymous
b) The currency has adoption / is among the most popular ones so that he can use it among people, shops etc
c) The currency is easy to use
d) The currency is liquid (plenty of exchange backing where he can convert to fiat, btc, precious metals etc) and has sufficient market depth to absorb larger amounts if necessary without the price getting affected too much
How people got their coins is of no concern to John.
If John wants to buy something privately, then: BTC/FIAT => DRK => purchase what he wants
If John wants to accept payments, then: OTHER PEOPLE WITH DRKs => him => he does whatever he wants with them (keeps them/converts them to FIAT/BTC/PMs/buys stuff with them etc)
So, how does that reality fit with your "game theory" assessment, in the real market? It doesn't. Because your view is so narrow that it only focuses on shitcoin speculation instead of real-world adoption (where DRK is already #2, behind BTC, in several sites that deal with PMs, gambling etc).