I feel as though this claim is very vague, as it does not describe specifically the topic. So I am going to assume this is about either A, Lego's, or B figure's (as in action figure's, or collection items), so keep that in mind moving forward. Now taking my stance, i feel that fan-made replicas are never legitimate, as they are not official, and are often times not the highest quality. and with the term "legitimate," they can never be legitimate, since they are not official, and I feel as though presenting them as such is a form of scamming.

At first, i was unable to see your argument, but now that i can clearly see your argument, I can shift my claim. A good, or High quality replica is obviously great, but i feel as though it should be presented as such; just like with shoes, and phones. No one wants to wear a fake pair of Jordans, and no one wants it to be known that they have a fake iPhone. High quality replicas are great, but they are not the official product, and people buy for the brand titles many times. and for your example with the arcade game's, I agree, they are sturdy, but the fact that they are good, or even better than the original, doesn't make them legitimate, since they are Fan-made.

Just because something feel's real, doesn't make it legitimate; Imagine someone using the worlds best VR headset, and they live their dream life for a short period. though it can feel entirely real, that simple realism fact, wont make it reality. Another example are with phone replicas; I can work day and night to make the best 1:1 iPhone replica, but that wont suddenly make it a real iPhone, as it was not made by apple, something can feel real, but not be legitimate.