Are all wars ultimately motivated by Greed?

How very convenient, by mere coincidence around 60 billion barrels of oil has been discovered within 150 miles of the Falkland Islands. Before you conclude this will save our economy from the effects of peak oil, that's approximately 2.75 years of global consumption and as in the North Sea would have a low EROEI (energy return on energy invested), i.e. it would require expensive oil rigs drilling hundreds of metres below the bottom of the Southern Atlantic Ocean. For more read Falklands oil prospects stir Anglo-Argentinian tensions

So far the UK government has spent tens of billions reoccupying and defending the largely desolate windswept Falkland Islands and its 1500 inhabitants. Why bother? Why did the Thatcher government not rehouse the inhabitants in the Hebrides back in 1982? It would have been much a cheaper option and saved several thousand lives.

I grew up in the 1960s and 70s, when the UK was at its least interventionist, at least outwardly. British soldiers struggled to keep peace in Northern Ireland and elsewhere seemed to be only deployed in multinational policing operations such as Cyprus. After public opposition to the Anglo-Israeli-French attempt to recapture the Suez Canal in 1956, The UK had amazingly refrained from deploying its troops in territories over which it had no jurisdiction. Notably Harold Wilson's 1964-70 government kept the UK out of the Vietnam War. Of course, that was just a façade, as the UK arms industry and military were fully integrated with NATO and the US military industrial complex and Britain continued to service colonial outposts such as Gibraltar and Hong Kong as well as deploying tens of thousands in its sector of West Germany. Yet despite relatively recent memories of the Second World War and the perceived threat of the Soviet Union, back in the 70s the British public were generally against the new mantra of preemptive interventionism. 30 years later British troops are stationed in Afghanistan, Iraq, the Balkans, Cyprus, Sierra Leone and numerous other outposts in official or unofficial capacities. And all along we are led to believe official pretexts for their presence.