Pivots depend on alot of factors. I changed the pivots on a Carbon Remedy after 2 years as they felt rough. I could have easily got another year out of it but the improved rear suspension on fresh bearings was a bigger difference than a shock service.
In the same time my slash that gets less wet weather use has perfectly smooth bearings in the same time. It’s very dependent on use.
I’ve previously had single pivot DH bikes that needed bearings every 2 years. I put this down to the extreme abuse they got from wet races/uplifts and then often long periods not being used, allowing them to rust.
I certainly notice less shock bushing wear and less shock service required on some multi-pivot bikes I’ve owned. I put this down to the shock being subjected to vastly lower twisting action, often positioned better to avoid mud spray and a design that is less reliant on the damper to control the rear wheel movement.