When a commodity price collapses, it’s only natural to see a shakeout among the companies that produce it. The weak go the wall and the strong salvage from the wreckage what they think will make them stronger.

Only, oil often doesn’t play by those rules, particularly outside the U.S.. Many of the world’s biggest companies are either entirely state-owned, or are sufficiently under the control of their respective governments as to thwart the process of natural selection. That’s why most of Europe’s big oil and gas national champions — France’s Total SA STOHF , Eni SpA EIPAF and Spain’s Repsol SA REPYY — have all been left cold by the news of Royal Dutch Shell’s RDSAF $70 billion merger with BG Group BRGYY .

But the apathetic reaction of U.S. oil stocks to the biggest oil deal since Exxon’s bid for Mobil 17 years ago is harder to explain. They’re all run for the benefit of shareholders and many are ripe for takeover. News of a big deal almost always fires speculation of more to come in the sector — especially when the buyer pays over the odds, as Shell quite clearly has done (it paid 42% more than BG’s average share price over the last three months). Yet, of the 93 components of the Dow Jones Oil & Gas Index, only a quarter–23 in all–were in positive territory in early trading Wednesday.

The reason is partly that the Shell/BG deal is pretty unique, a reaction to the shale revolution rather than an influence on it. Both companies specialize in high-cost technologies (liquefied natural gas and deepwater offshore drilling) whose economics have been badly hit by the increased availability of cheap oil and gas in north America. Where they have tried shale themselves, they generally haven’t got very far with it, either in Alaska, or more recently, in South Africa and Ukraine. Their merger is basically a doubling-down on pre-shale bets on long-term demand from emerging markets.

But there is another factor closer to home that may explain the lack of reaction. Buyers and sellers of U.S. shale oil and gas companies are still too far apart in their heads for deals to get done.

A typical case in point is Whiting Petroleum Inc. WLL , the largest producer in the North Dakota Bakken shale region since buying Kodiak Oil & Gas (and its $2.2 billion debt pile) last year. Whiting had to go through with a deeply-discounted $1.05 billion stock offering in March after failing to find a buyer in the previous three months, according to Bloomberg. Other shale producers too (such as Linn Energy LLC, Laredo Petroleum Inc, Oasis Petroleum Inc, Encana Corp, Corrizo Oil & Gas Inc. etc) are being kept alive by investors who prefer to double down rather than cut and run, hoping that a rebound in oil prices is just around the corner.

According to figures from Dealogic, U.S. oil and gas companies have raised $13.9 billion in equity so far this year, almost as much as in the whole of 2010. Tellingly, none of that has come through the IPO market. By contrast, only $9 billion in M&A activity was done in the sector since Jan. 1, compared to $165 billion last year.

The ratio of 2nd-tier US oil and gas companies' debt-to-assets nearly doubled between 2006-13
Leverage at 2nd-tier US oil and gas companies nearly doubled between 2006-13

 

Such bets are made easier by the fact that weak economic data has pushed back expectations of that dreadful day when the Federal Reserve stops giving money away for free, making it easier for the sector to keep on pushing an $850 billion debt pile ahead of it.

So, if there is a wave of M&A to be triggered by the Shell/BG deal, it might not necessarily be among the U.S. producers, at least not immediately. The logic of the Shell/BG deal is to give the two companies more leverage over the sources of their biggest costs–service providers. Small wonder that the prices of companies like AMEC Foster Wheeler Plc and Norway’s Seadrill ASA SDRL were down heavily in Europe today.

The merger of Halliburton Inc. and Baker Hughes Inc. has already shown that consolidation isn’t restricted to the producers. With the whole industry trying desperately to crush costs, it would a big surprise if the action stopped there.