'The idea becomes a machine that makes the art.'
This simple sentence from Sol LeWitt's 1967 Paragraphs on Conceptual Art is often overlooked.
Because in this sense a Mark Rothko painting can easily be reformulated as a conceptual artwork by stating that he had an idea to paint large blocks of colors by overlapping heavily layers of oil paint.
While an idea has nearly universal accessibility, art exists only in its making.
Take Anish Kapoor's popular mirror works, like Vertigo from 2008.
In Kapoor's mind they open up new ways of envisioning the world, but conceptually they explicate nothing a metal spoon can't show me. Even considering its material, polished stainless steel, is straightforward enough.
Where things get difficult is when you actually have to produce this optical effect on the scale Kapoor does. First you will have to find a foundry capable of molding and shaping a sufficiently large piece of fairly thick stainless steel. This is perhaps the most difficult part, but not the most laborious. It requires days, if not weeks, of polishing to make a raw piece of metal truly shine like a mirror, which is not aided in any way by the shape of the structure.
And then I haven't even mentioned moving the structure in space, which due to its size, weight and tendency to scratch must be an absolute nightmare.
So while the effect of Kapoor's work can be found in nearly every cutlery tray, the exact expectations of scale and finish require a significant amount of resources and organisation that few people have access to.