That’s the distinction that Retro isn’t understanding. Take your example: You weren’t able to use an external drive as an engine prime source drive. There wasn’t anything on the advertising, or the manual, or the billeted lists that said “You can use an external drive as a prime source”. Later on denon improves things so that you could, but they weren’t saying from day 1 , at least not that I can see from any of the old “Announcing… “ posts.
And that’s true of pretty much everything. The original prime, the sc5000, advertised onboard analysing and it did onboard analysing, it advertised beatgrids and it offered beatgrids, it said it had onboard bpm calculation and it did have it.
Now yes, there are hundreds of requests for making those features perform differently, or adding whole new requests and features but we’re not actually missing anything that was listed in those original announcement posts