For those that are losing it altogether, I think you'll find that at those airports the average movements per hour are one or less. In many general aviation airports in this country, and indeed in other countries, you have far more activity than that without any air traffic services. The pilots use such things as UNICOMs, which work quite satisfactorily. There are well-established procedures for operating it on controlled airports that have been there for fifty years.
What you're really identifying here are airports where the level of traffic has fallen to literally one or less movements per hour.