It's all variables and it's all risk. Whether or not you choose to accept it is the question. You can't just make a blanket statement of "if it's not under $2 per GH, it'll never ROI." If the price of BTC shoots up to $1000 tomorrow, that $2 per GH will ROI just fine.
If you need BTC to skyrocket to ROI, then you're far better off just buying the BTC.
NO NO NO! We need the hobby miners whether they don't ROI with their own rigs at their homes, or via paying us the inflated rate to do the dirty hobby mining for them.
Recall, back in the good ol' days, miners had to man their hobby rigs 24/7, never having time to enjoy their negative ROI when the hardware finally arrived a couple weeks late. Today, they have the ability to pay us to do said dirty work, thus now allowing them to go out and enjoy the good life (perhaps with somebody's wife) while they're negative ROI;ing as we ROTFLOMFAO.
Miner Technologies is doing it
to for the little guys, clearly wanting to eliminate them big mining pharm entity thingies, putting the power back into the little guys' hands. At least that's how it's taught at Penn State and what nut, if my Bulgarian lyin' ass is not mistaken.