In modern warfare, you don’t get these for free. If you’re trying to yoink from a fellow nation-state, you risk your own factories being bombed. If you’re up against a less sophisticated foe, you still sacrifice industrial production and diplomatic goodwill in excess of any base resource gains.
It’s cheaper and more fruitful to trade for those goods than it is to steal them. (Coups are no exception. They disrupt the economy and jeopardise the security situation. Much simpler to trade with Tehran than try for a coup that doesn’t result in civil war or blowback.)
Which tends to have effects similar to what you've described. Land that isn't near a potential threat can be invested in much more heavily. Borders are easier to defend, etc.
But improvement to existing resources tends to be more attractive to those with the most resources already.
Of course, it's much easier and cheaper these days to use your intelligence services to stage a coup in that country so that your corporations can get their bananas for free, or, planting fake WMD intelligence at the UN so you can justify going in guns blazing and your corporations can make money through weapons sales, oil extraction, logistics and reconstruction on the back of taxpayers and the intelligence services by running heroin to fund their black ops.