I live in a city. Opening my wifi menu on my MBP, I see dozens of networks. I've never really experienced any spikes like you mentioned every with gaming or video calls.
It probably heavily depends on your networking equipment. Most modern APs should have interference detection, MIMO, beamforming, variable channel width, etc., but if you're on 2.4GHz in a crowded building with thin walls I'd imagine things could get pretty hairy. Even in ideal conditions, wireless will have far more dropped packets, transport overhead, power draw, etc.