Notably for some reason you chose not to include the part where they also say about Mac OS:
Demand-side use (end-user): open
Supply-side user (application developer): open
It is not a walled garden in any way that they define a walled garden.
Here is the definition from the page you link: “A closed platform, walled garden, or closed ecosystem[1][2] is a software system wherein the carrier or service provider has control over applications, content, and media, and restricts convenient access to non-approved applicants or content. This is in contrast to an open platform, wherein consumers generally have unrestricted access to applications and content.“
It doesn’t apply to Mac OS.
Restricting installation of the operating system itself on other hardware just isn’t part of the definition.
No matter how much you selectively copy and paste from a Wikipedia page, it will not say what you claim it is saying.
Trying to say any restriction of use means a walled garden is akin to saying any software that isn’t completely free is a walled garden.
That just isn’t what the term means.