The price you quote is the cost of yearly subscription for just a single program (per station). An architect or engineer will use ~5 such programs on a daily basis for various modeling/analysis tasks.

What "ISV certified" means depends quite a bit on what is required.

For a lot of the workloads a sub 1000 PC is enough (I'm in the AEC software industry and am quite familiar what we are talking about).

Take into account that most software in the domain we are discussing is decades old. Some things would work just fine on the lowliest PC you can buy from the cheapest vendor. And yes, sometimes even the most beefiest machine is not enough.

Yes but Solid Works or Siemens PLX starts at about $3500 per seat, so the laptop is still going to be only a percentage of the total cost. You can run on GeForce gpus for about $1000 but run the risk of something not being guaranteed.