Really? There is a large war going on right now and the key material is chips. Drone don't use a lot of steel, neither do missiles or modern airplanes.

Yes you need artillery and particularly shells. But you are so much more limited by the capacity of your munition factories that how much steel you have would not be an issue. One of the main things you would need for a new munitions factory is trained workers.

The World Wars were wars of mass mobilization and industrial capacity. People went into the first thinking cavalry was important, the second thinking battleships still mattered. My point is I have no idea what the next great war might be like, but thinking the winner will be who chugs out the most tanks in five years may be looking in the rear view mirror.

You can't occupy territory with drones (yet). You will need people and moving people in a drone-infested environment will mean protecting them with armoured vehicles. Yes, these vehicles will need enhancements and other new tech to counter drones, but armoured vehicles aren't going away (MAYBE the tank's days are numbered, though).

If you are really interested in this, I highly recommend subscribing to war on the rocks. Their articles and paid podcasts have legit defense industry people publishing studies on this subject. https://warontherocks.com

It's a myth that battleships didn't matter in WWII. They ended up being critically important in the Pacific Theater for carrier escort and amphibious fire support. They didn't stop mattering until the widespread deployment of guided missiles and other precision munitions.

Drones are only part of the equation you need to be able to forge things