Dispatch based on marginal cost makes sense, as that ensures that the lowest marginal cost generators will be used to provide the demand.

But yes, increasing penetration of variable renewable energy like wind and solar will mean that the price will vary wildly. That means that players in the market will need to be hedged to insure them against too high/low prices.

Also it wouldn't surprise me if various capacity market type mechanisms were to become more popular and constitute a bigger share of the money flows in the electricity market as a whole.