In support of your thesis, the US frackers are getting more from each hole, as the various underlying technologies which make up a fracked hole continue to develop and improve.
Not only that but the current weakness has driven much of the over leveraged
weak players into bankruptcy, thus they are being bought by the stronger
players at bargain prices, allowing future production to continue at an even
lower cost basis as the debt loads are no longer present.
The only way oil is going to sustain at $60 or higher, outside of seasonal
spikes such as US gulf coast hurricanes or summer driving season, is if
there is a major, extended war involving multiple oil producing
countries, or political leadership changes and the monetary and
regulatory environments change such that the world economy sees
a significant increase.