"High frequency of non-running 120s with shot bushings-and-Monroes (painted blue) ought to be noted. And no: bushings don't fail when used as designed."

Can't believe you actually think this is true. Bushings are replacement items. And I am not surprised that neglected 120s all over the place have inexpensive shocks and blown bushings.... Many of them probably also suffer from; worn out tires and rusted out mufflers/tail pipes, need new plugs, fuel line is clogged etc etc....:) To each their own.

"Am surprised at response implying engineering design isn't a factor"

Of course engineering is a factor....just maybe not your interpretation of it.
Specifically,

1. how shocks were tuned in the 60s in Sweden given that the roads were mostly dirt.

2. whether softer compression would increase wear that dramatically.
For sure if you put a super stiff shock in there there will be less movement/wear, but the point of suspension is to move. I put the poly bushings on a couple of my 120s, and I have to say I like being back on the rubber with my 220, much smoother/quieter.

Anyhow most folks here say they find the KYBs too stiff for regular driving and that's enough for me. I use this board for the collective knowledge, and it has served me well over the years, there are many different opinions here, and we all get to pick and choose.
--
Patrick, '68 220, '92 Eurovan , '53 PD4104 (highway coach conversion).