Absolutely true. Not all enemy a PC group encounters are going to be disorganised rabble, and it's a bit more work than most of us want to do in the middle of a game to research the proper composition.
Still, we all struggled through this far.
Of course by 2000, even regular professional units may no longer even superficially resemble their prewar makeup. A section/squad of 9-12 men which used to include one, maybe two light machineguns plus a grenade launcher or two is likely to number about half a dozen with a heavier emphasis on firepower. Some of those members might also be non-combat troops, or at least were in their last assignment, and sent into infantry units as replacements once their role as cook, clerk, band member, etc becomes irrelevant.
Regardless of nationality, I would expect a commander would want approximately half his infantry with automatic weapons capable of sustained fire (ie belt fed or extended mags) and the other half armed with grenade launchers or similar explosive type weapons. This would go some way towards countering the lack of personell, but the loss of even a simgle soldier would significantly downgrade the units effectiveness. Unfortunately smaller units also mean less flexability - less able to split into teams and attack a position for several angles, etc...