In Stalingrad with Full Access all soldier tiers (I / II / III) costs 18 bronze from lvl 4 to lvl 5.
In other campaigns Tier I costs 18 bronze (lvl 4 to 5), Tier II costs 54 bronze (lvl 4 to 5) and Tier III costs 72 bronze (lvl 4 to 5), so it’s even more than OP said.
Totally agree with you. Nevertheless:
If I need bronze orders for soldiers I buy tier 3 soldiers and sell them. Gives you minimum 3 cards. Yesterday I bought 10 tier 3 assaulters and gained 200 bronze cards due to 4 and 5 star soldiers.
I know it’s like gambling and doesn’t excuse the fact the bronze orders are always lacking.