The SC protocol changes the incentive structure that gives Bitcoin its value. Miners will over time have to MM Bitcoin not for profit but for some other reason.
Decentralized Exchange can be done using existing technologies not need to introduce a change to the prototypical that introduces disincentives for miners to mine Bitcoin.
if there is was any chance that what i say was true student it be worth trying to understand why that is?
But that's the point my friend! Sidechains are not decentralized exchange for altcoins! It is much more interesting than that.
And you concern about miners abandoning the mainchain is not very plausible considering its block subsidy will continue for a long, long time and every miners will want a piece of that.