So, here's a different take for you:
In the future there's a good possibility most mining will be done by energy companies. They need to produce more energy than people consume for peak spikes... This also means they can have ASICs themselves to recoup money while they burn energy no one else is using.
If you're mining for sub penny per kWh do you really care about subsidy vs tx fee? You're basically getting paid for free so it doesn't matter.