Amazon seems to targeting the wrong category of the art market. I can see people buying works for $50-$2,000. But the idea of someone paying 1.5 mil for a Monet on Amazon is both ridiculous and unlikely.
On the first point and in my experience, the majority of traditional galleries rarely list prices for art. That leaves no chance to be surprised at accessibility ("Who would've thought that Dali lithograph would be $2k? That's worth it just to say I have a Dali on my wall.") or to start saving towards a defined goal ("$6,000. And I love it. If I get that end of financial year bonus..."). How many people would just think "If I have to ask, I can't afford it" and walk away.
A piece or something similar might be cheaper in a specific gallery, but it's quite possible that a newcomer would have little idea about that. Or no way of easily telling if the gallery itself was listing POA.
On the second point, someone recently offered a $1m+ tour package that travelled to every UNESCO world heritage site (hundreds of them), across a span of 1-2 years. They found a buyer.
There is a growing interest in wine from an inexperienced Chinese market with money to spend and I could see there being a similar market for Western art presented accessibly too.
~2006 I tried to create an online art marketplace (this was a direct-from-artist marketplace from $50 to $50,000) and one of the main problems was that buying online made the work feel a bit cheaper. That's a stigma that will die off.
All you need to sell work remotely is trusting the brand you're buying through (Amazon) and being familiar with the artist you're buying.
A bricks-and-mortar comparison might be Target and a higher-end store like Lord & Taylor or Nordstrom's. Amazon is more like Target - it has a decent brand, but you wouldn't really expect to find thousand dollar paintings there. You could, perhaps, expect to find such paintings at a "higher end" store, though.
But, I could be wrong. I just don't think the people spending millions on paintings are the people cruising Amazon for a deal. The online marketplace for exclusive artworks is a different site IMO.
It does seem to be gallery prices for the commodity art at the low end. But these are just the people that were first in. If we get that race to the bottom among artists, we might see some good stuff for a good price.
eBay has a lot of listings priced over 6 digits.
Both are positioning themselves as the go-to site for buying anything, recognizing that entries in a web-searchable database costs next to nothing regardless of how many digits in the offered price tag.
Also, try to realize what this means for Asian bidders who may not have the time (or inclination) to fly over to the West to purchase a work. Or vice-versa.