One of the biggest problem Apple has is the naming convention for the Apple TV, Apple TV+, and the Apple TV app.
Most non-tech people do not know the difference between these things, and while Apple does advertise ATV+, most people have no idea what the ATV HW actually is.
While it is a fact, I wouldn't say it is well known outside of the tech world, and probably the Apple tech world.
I have heard similar statements from many people in the wild. Also, that many people think that the ATV is an actual television.
Apple sucks at advertising the ATV, and while it advertises ATV+ like crazy, many people do not know that ATV+ content can be viewed on non-Apple HW.
I think that is the point of the OP, Apple should advertise that ATV+ can be used on non-Apple HW.