Obviously not much. The point I was trying to make was that a small player probably can't compete with Amazon on price, but they may be able to compete some other way.
Is it even a problem if they can't compete with Amazon on price? Generally the reason to fear monopolies is abuse of market capture for profit. If you own all the corn, you can set the price. But Amazon doesn't own all the commerce - it just undercuts everyone. But that is a win for consumers until Amazon tries to exploit its position.
But the moment they do that, right there is where you can undercut Amazon. If they are abusing their competitive advantage by the nature of abusing it they are giving it up.
At worse, they raise prices circumstantially to maximize profit, but that is more the benefits of winning the market than of exploiting a monopoly, because they would still be overall cheaper than any competitor could manage.
As long as Amazon is cheaper (and not exploiting employees) than what a competitor could do, the consumer is winning.
As you've described it, the consumer's "win" is determined by Amazon's competitors. Every private advantage Amazon has serves to undercut the profits a competitor would need to develop their own productivity gains. Those are the gains that would actually show up for consumers. How are they winning?
Obviously not much. The point I was trying to make was that a small player probably can't compete with Amazon on price, but they may be able to compete some other way.