Relic still has 300 or so employees. That still seems like an awful lot for maintenance releases. If pushing updates through Steam is as easy as it looks, I'd bet my PMP certification that a competent project manager could get the game fixed in a couple months with about 1/4 of those 300 employees.
CoH3 is not the sole exclusive active relic game.
There is AoE4 and SM2 development too and these people are not doing all 3 projects at once, this much I can assure you, they have separate teams. For all we know, CoH3 team could be 10 guys now.