I have had very few "good small sound system" experiences.

Perhaps the problem is the low prices "small operators" get (maybe that's "all operators").

Quick changeovers between artists also directly influeces the style of music and the type of artists that "fit" the bill.

Here, in a good "acoustic" venue, no PA is an advantage. Otherwise, where PAs are essential (and that is many many venues) time, thoroughness, empathy and communication are all very important and can be in very short supply.