Russia invaded Afghanistan for the same reason the US invaded Vietnam - an imperative to spread their ideology. Both failed for the same reason too. But natural resources weren’t even in the frame.
there are still plenty of drivers for such a war besides ideology.
Natural resources, they don't need to be profitable during the war, if the prospect of future peaceful taxation after victory is alluring enough.
Natural resources, the natural resources don't need to reside in the target country, the politicians, war industry etc in the invading country can use their profit to gain a bigger share of the resources and economy at home.
Dick length contest, remember when for one of the missing planes a few years ago how the larger nations refused to share any military RADAR imagery, since it would reveal the state of their art. During peacetime you can develop and test future war technologies, but there is always the paranoia that you don't know how far potential future enemies are. So they need a "playground" and compare genitals, and test systems in practice... but neither power wants to wage war on their own soil, nor risk all-out war with the other power on their soil... so they squash the little powers, especially those that start gaining independence and would otherwise end up paying tax to neither superpower. In this perspective the war is in fact a common goal for the "animous" superpowers...
