I've been reading all of the "Is mining still profitable?" questions, and the consensus appears to be the following: Yes, difficulty is increasing, but profitability is uncertain due to the speculative nature of mining.
What incentive is there to keep miners on the Bitcoin blockchain? If their ROI is positive, but marginal return is decreasing, why not switch to mining a new currency?
I'm new to Bitcoin, I apologize if the question is unclear or illogical.