To me, a REAL model should be very well constructed - I mean that there is absolutely no sloppy construction - the finesse of the detail is all important - the cleanliness of the paint job is imperative.
Then there's the most important part - weathering the thing to make it look REAL.
Then, and only then, is it a "scale replica" - as opposed to a "model".
A model can be anything - cheap and nasty, small or large, expensive or cheap.
But a "scale replica" looks like the real thing that's been shrunk. Put gas in it and drive it away.