As @Riverside points out, in general people are just suggesting that Mr Braben would probably not want to have the value of his explicit promise be completely rubbished.
I have the Quattro available (and used) on two accounts and would have no problem with it being made available to others (and hence my to other accounts too). No doubt we would then replace these threads with other whining "I want" threads - like "I need a Founder's Decal" or whatever...
People should just grow up and stop whining about something so unimportant as not having access to an imaginary space ship in an imaginary space travel game.
If we are going to not let promises fall to rubbish status, then I may not be alack for complaints to bring up with Mr. Braben, starting with offline mode, and how its cancelling was announced late and only implicitly (...although here, too, I don't doubt you and I are going to have very differing ideas of what is and what isn't).
My personal diving into this thread is more of a matter of principle, with regard to exclusives as a whole (including console exclusives; Never got why any developer wouldn't want as many people as possible to enjoy the fruits of their hard labour, and showing their appreciation through their wallets... You know: I could fully respect it, if somebody didn't want to support a platform out of sheer being too lazy to do a port, even if it would have been highly profitable; But to "artificially" limit proliferation, out of a platform holder's purchasing a market advantage (effectively covering your unit sales losses): Blah)!
I couldn't care much less about any mediocre ship (...which I do happen to have), but there was this period where game companies would strike exclusivity deals with vendors, parcelling up not only pointless tat, but good, solid, lovingly built, and world-building chapters of their games, between them, so if you wanted the entire game, you had to buy several copies, from different shops. -Not the same magnitude by a long shot, granted, but what is the harm in reminding publishers now and again, that there is distaste for the practice, and not offering them so much as a fingernail clipping worth of encouragement.
On a more general note, regarding sticking to one's guns: I fully expect a sensible person, given good reason, to be able to change their mind, and correct course - away from any looming ice berg.
The amazing destructive proclivity of people to double down on being wrong, when presented with evidence, no matter how crushing, is utterly flabberghasting. -In the minds of some, it is apparently seen as: "strength", to never admit a mistake, even to oneself.