That seems... wrong? Say Google offers you 2 TB of storage space for 1 year for $100. You're saying that's preventing you from simultaneously paying Microsoft $100 for > 2 TB of storage storage? Or that that's preventing Google from giving someone else 2 TB of storage space for > $100? What exactly prevents both parties from doing this with multiple counterparties?

If you have lots of X, sure. But instead of something incredibly fungible like storage space, suppose I had instead agreed to sell you the Empire State building.

I thought the claim was "all contracts are a restraint", not "there exists a contract that is a restraint"?