[kube-system]

The math absolutely does check out, lets say, for an addressable market of 100k purchasers:

(and I'll be generous and I'll pretend Walmart has zero fees)

Amazon: ($5 selling price - $3 fees - 0.80 COGS) * (100k * 35%) = $42,000

Walmart: ($2 selling price - $0 fees - 0.80 COGS) * (100k * 7%) = $8,400

And even if they price the same on Walmart as they would on Amazon: ($5 selling price - $0 fees - 0.80 COGS) * (100k * 7%) = $29,400

See the issue? The problem is that one seller on Amazon moving to another platform won't change the fact that Amazon has the majority market share. That's how market momentum works and it's why we have antitrust laws.

Even with exorbitant fees, they are still where sellers need to be. And they are using this market share to force sellers into overpricing on other platforms so that they maintain this unfair position.

[jjk166]

Walmart is not all-non amazon customers.

If Amazon's market share is 35%, then the non-amazon customers comprise the other 65% (which, being greater than 50%, constitutes "most").

Amazon: ($5 selling price - $3 fees - 0.80 COGS) * (100k * 35%) = $42,000

Not-Amazon: ($2 selling price - $0 fees - 0.80 COGS) * (100k * 65%) = $78,000

If a seller raises prices to match Amazon, they can be undercut elsewhere by those willing to forgo Amazon for the larger overall market share.

Amazon is convenient to small sellers in that they offer more customers on a single site than any other, and with limited bandwidth sellers logically want to minimize how many different sites they need to interact with, but charging for convenience is not inherently anticompetitive behavior. Amazon may have abused it's position in the particulars of its MFN implementation, but MFNs in general are fine.

[kube-system]

There are two reasons why that 65% number is wildly unrealistic:

1. We're ignoring fixed costs associated with onboarding with an ecommerce platform. Selling on one website has significantly lower fixed costs than it is to sell on every ecommerce site on the internet minus one. We're talking thousands upon thousands of retailers, not a handful. If what you were thinking is that they could sell across the next 5 to 10 most popular ecommerce marketplaces, you're somewhere between 15% and 20% marketshare.

A more realistic number for that strategy is:

Not-Amazon: ($2 selling price - $0 fees - 0.80 COGS) * (100k * 17%) = $20,400

https://www.statista.com/statistics/274255/market-share-of-t...

2. Not all ecommerce sites represented in that 65% permit third party sellers. You can't just sign up and sell your stuff. You may have to convince their buyers to stock your product. This is not easy or cheap.