We can recreate lots of things, but almost always appreciate the true version better. It’s why it’s cooler to see the Mona Lisa than to see a poster print of it.
Why? As far as I can tell, other than just for the sake of the view being “natural” or having some weird color issues due to time and radiation and oxidization, nobody wants/needs the actual painting anymore.
Reason: because even when it’s identical or even inferior, the touch of nature is just… nice.
A painting has a 3 dimensional texture to the paint, while a poster is inevitably flat. Different paint compositions will also reflect light differently, while a poster won't.
So, yeah, having the real painting has additional value.
I wouldn't pay much for a painting anyway. I have several paintings and posters up on the walls, and they're interesting for a time, and then I just don't see them anymore. They're just part of the wall.
I think you just described the placebo effect!
Unfortunately, as much as I'd like to pick and choose when it effects me, I am a mere mortal, as are many I believe.