The problem is that to purchase art & antiques well,
you must have expertise in the area. My second cousin got rich in the antique business, but that is because he went into it with significant knowledge and learned as he went along. He did NOT buy his stuff from scam artists, but from flea markets and bazaars around the World.
Only an expert is likely to make money by investing in art, antiques, coins, etc. The ordinary person is just going to become chum for the sharks.