[sidlls]

Let’s compare like to like, though. In theory anyone could start a site to provide a marketplace for sellers for $5/month in hosting and maybe a few hundred bucks in upwork costs for standing up a php e-commerce platform. In practice the cost to compete with Amazon is much higher.

[lotsofpulp]

Competition with any larger entity is more difficult in metrics that are improved by scaling.

My point was that Amazon has many capable competitors.

[sidlls]

The barrier to entry in that market (Amazon and its competitors) is staggering compared to the barrier to entry into the general "sell stuff online" market.

I also don't agree with your list of competitors. Amazon is more like a mall, while almost uniformly the others you list are more like a retailer acting as a middle-man between wholesalers and the general public. I'd agree with Aliexpress and maybe Walmart.

It's just not a healthy market.