I’m not sure we disagree here. The stuff is getting more expensive all over, not less. That is declining productivity (if you measure output in Bbl not USD).
If you still think we need $100 oil for hydraulic fracturing to be a profitable stimulation method, we don't agree.
I hate making predictions. The oil price has already dropped farther than I thought it could in the past 6 months. But I do not see a long term (multiple years) with prices staying ~$50. They will climb over the next few years. $70? $80??, $90???
Unless something else greatly changes, like a really bad global economy where the demand actually falls for several quarters in a row. Or a dozen different things that greatly impact global price.
But in either case, hydraulic fracturing is not over in the US or the rest of the world.
Cheers!