Theres a pretty good argument to be made that it nearly eliminates piracy, and is good for business too.
the harm isn't consumer oriented, since it's somewhat diffuse, it's about concentration of market power in the industry.
we could live in a world where you target one distribution platform, and phone vendors compete to police malware, but instead we have walled gardens that police content & economically lock you to their environments and don't even do a good job about malware
That's true, but that's not how anti-trust law works in the US unfortunately. It's consumer-harm based.