Considering the cultural and historical significance of the Mona Lisa, I can't imagine you would be allowed to keep it out in the open, even if you did somehow manage to buy it from the state.

Besides, you wouldn't want anything to happen to it considering how much you would've paid for it. Plus you would forever be known as the dickhead that destroyed the Mona Lisa, like Miles.

As for the wood thing, you're right, but after hundreds of years that poplar might be able to go up like canvas. But I can also imagine The Louvre giving Miles a fake. After all, Mus- I mean Miles is an idiot.