The argument I'm trying to make is that if you even if you remove forced expansion by means of resources that run out, you're going to have forced expansion by means of competition because if you don't do it, your opponent will and you will be outgunned a bit later on in the game.
It's a simple principle really. For any and every game that relies on "resources = buildings+units", it is advantageous to increase your resources, since that will result in an increase in buildings and units that win you the game.
The only real difference in terms of expansion between SupCom and 'traditional' RTS is that SupCom is just a hell of a lot slower.
So if that means that any game with gatherable resources, regardless which game, will feature economy expanding one way or another, what exactly is the problem?
The fact that resources actually run out in games like Starcraft?
Spectate one starcraft match, not even on a pro level, just one, and you'll find that long before the first mineral field is depleted, there will already be 2 or more expansions per side anyway. For most matches, actually, you'll find one side has already won before the mineral field is depleted.
The only reason the depletion is there is to prevent turtling being too effective. If there wasn't such a limit, every single SC match would end in some monstrous battle where both teams were at their 200 unit cap. Boring as hell, in other words.
If having to expand elicits a feeling of claustrophobia in you, that means you either haven't scouted the area properly, haven't got a clue where the enemy is or are simply too fussy about it. Losing one expansion is not always a big deal, especially if you have more than one. You can always cancel if it's still building.
Actually, in those games, you have to have really good build strategies to survive. If you CAN turtle all day long, it's because you have built really good defenses, built in really good formations, and have a good idea of what your opponent is going to attack with. That is a far cry from "doing nothing".
So, in short, the first half hour of the match is going to consist of two players spamming their bases with defense turrets and massproducing units while repeating a canned build order and occasionally sending a scout unit over to the opposite base to find out what's happening? If you compare that to a typical SC match, that might be won in 41 minutes, it might be won in 8 minutes with a rush build, it might be decided by a crucial battle some 10 minutes in, etc... There's just a lot more to the strategies that you can use than just 'building units'. And that's
because of the constant fight for resources. If you let your guard down somewhere in the midgame, that could mean you lose out on that crucial expansion near a chokepoint.