What high oil prices do is allow smaller players to start in the market. This how the oilsands started development. Encana and Nexan are two oil companies in Canada became world players because of high oil prices.
The other thing with US Oil Shale or Canadian Oil Sands is that they are not controlled by nationalized oil companies. Exxon, Chevron and Shell are highly invested in Canada and the US for this reason.
Most of these companies were screwed over by nationalized oil in Venezuela and the middle east, so they like to make their investments in the US Canada and England.
I'm certainly no expert. However...
High oil prices do allow small players into the market, but it seems to me that would work against it's self in that as they more oil produced through low margin methods it becomes less attractive to increase when far higher margins are available. In other words, it's not going to do much and if it did, it would against itself because as oil goes down that method gets even less profit.
What is the percentage of oil produce currently with shale or oil sand versus land based drilling?
Right now, what would some one want to invest in? Drilling or shale and oilsands?
To me, it's all about money in drilling. these oil companies are probably just protecting their market share by investing in shale and oilsand but will they ever produce it to the point that it makes a difference? why should they when the profit margin on drilled oil is so high? In the meantime maybe they have most of the leases and permits on shale and oilsand but aren't motivated to used them.
Besides this is about off shore drilling last i checked.
