On a related note, I don't think it was the _cause_, but it is true that both the military and the people fighting them benefit financially from prolongation of hostilities. (The former get access to all the $$ going into Chechnya, and the later get $$ from Islamic fundies abroad.)
There is a somewhat paranoid theory of economic history that states that heroin is at the root of all this-- "self-determination for drug-dealers," "poppy pipelines," --- arguing that Kosovar secession was a way to expand transit of heroin from Albania (the gateway to Europe for heroin from Southwest Asia, i.e. Afghanistan) and that the invasion of Afghanistan was was the way to restore poppy cultivation. Chechnya was to become the transit point for movement into all of Russia, with the additional benefit of threatening oil pipelines and pipeline revenues important to Russia.
This argument is not without merit-- as the role of heroin in sustaining and prolonging the war in SE Asia has been documented.