Digital silicon design is fairly simple in principle. It's hard because there are billions of transistors to route

PCB design on the other hand more often then not has outside constrains like mechanical, thermal an RF design

I think the amount of reuse is a big difference. IC tools build on characterized cells with a lot of the rules already encoded. With PCBs, even when you're reusing a reference circuit, you're often manually carrying over the constraints and figuring out which layout decisions mattered. A lot of the engineering gets repeated rather than traveling with the design. That's something we're trying to improve with atopile.