> The side that wins will be the one that runs out of resources last.

This is true for any military conflict and always has been. It's basically a game of resource denial/destruction.

If you poke through all the propaganda, ideology, etc. most wars boil down to which side has the best economics and can best deny access to essential resources for the other side in order to gain access to resources the other side controls (oil, minerals, land, water ways, trade routes, etc.).

Many modern conflicts are actually proxy wars where large countries subsidize minor conflicts in a plausibly deniable but otherwise very open way. China, the US, EU, Russia, the Saudi's, etc. are all parties in such conflicts and they are fighting against each other and with each other depending on where you look (Middle East, Africa, South America, etc.). In the background you have trade relation ships, oil & minerals, and economical sanctions. And in some parts of the world water access. Those are the resources that sustain conflicts.

Modern weaponry changes the tactics. But the strategy is always the same: go after resource access and you might win. You can see that happening in Ukraine and if China goes there, it will be a factor in Taiwan. It's why they mainly talk about that without going there. China is much smarter than Russia on this.