If I go back to pre living in Japan, I have spent over an hour in the immigration lines, certainly not as frequent as it seems to happen now. Some of my trips back earlier this year, the visitors' line was absurd. But it was basically a Haneda issue, I never saw anything similar in Narita.

It does beg the question of where the officer were sent, as they would be government employees and not possible to lay off just for the reason that their job was not needed for 3 years. But the recruitment and training may not have kept up with age retirements and that is why they lack agents. My impression is that when the lines are bad, not all counters are open, probably meaning there are not enough agents to man them.