> I'm kind of taken aback
Wow, did you seriously paste a link without reading it? Open Markets Institute did not file an amicus brief in Epic vs Apple. What you linked to is an amicus brief in the matter of Shah vs VHS San Antonio, a substantially different case which pre-dates the Epic lawsuit. Seriously, click on your own link.
OMI did release two paragraphs about Epic vs Apple in the form of a press release. Did you think that was an amicus brief? I'm starting to think that maybe you don't know what an amicus brief is.
> this is already disallowed under the Sherman act
No, it isn't. You do know that the Sherman act doesn't make it illegal to operate a monopoly, right?
> If an OS maker had sued Apple for tying a device to the OS, it would be illegal under the Sherman act too.
You've just demonstrated that you don't understand what "tying" is in the context of antitrust.