lets try proof by exhaustion:

in those jurisdictions where either price discrimination or locking hardware are not illegal, it is typically perfectly legal to reverse engineer for compatibility purposes. So nothing prevents such resellers from upping their game and learning a thing or two about link training and general SDRAM bringup.

Once they have acquired the knowledge legally in such jurisdictions the product just flows in the other jurisdictions anyway.

Courts upheld the monopolistic position of microsoft etc. for decades, but respect has no finality, "re" + "spect" to review, so later such companies were fined for their decades long transgressions.

But during those decades it may appear legal to the average consumer.

Inaction is not permission.

You'd be well advised to remember there is a world beyond your visible horizon.

Lots of things aren't illegal... unless you do them for illegal purposes.

I doubt antitrust would get anywhere on this RAM issue, but antitrust law is not defined in terms of either of those categories.