You can, if you are willing to pay the price, get laminate down to 20mm - so while 40mm might be standard, it is certainly not the default option. I won't profess to know why you won't often see a solid worktop at 40mm, but it is possible to spec that in certain materials.
If you were going solely on looks, as you seem to be alluding to, why would you ever go for solid over laminate? It has to be based on more than just looks, doesn't it?
If you were going solely on looks, as you seem to be alluding to, why would you ever go for solid over laminate? It has to be based on more than just looks, doesn't it?