I've always said the Ztr is the Cadillac of lawn mowers, while great to have it's more of a show boat and not very cost efficient.
When you speak of them being heavier on the truck, that also results in more wear and tear.
The trucks are harder to drive when a Z is in back, and it costs more to get it down the road, too.
The Walk behinds are a bit slower on turf but you are right, the decrease in production can be
explained away with the decrease in damage as well.
ONLY on very large properties does the Ztr truly come out ahead.
Glad to see at least one other person besides myself has noticed this.