Zero Hit Points:
When any creature is brought to 0 hit points (optionally as low as -3 hit points if from the same blow which brought the total to 0), it is unconscious. In each of the next succeeding rounds 1 additional (negative) point will be lost until -10 is reached and the creature dies. Such loss and death are caused from bleeding, shock, convulsions, non-respiration, and similar causes. It ceases immediately on any round a friendly creature administers aid to the unconscious one. Aid consists of binding wounds, starting respiration, administering a draught (spirits, healing potion, etc.), or otherwise doing whatever is necessary to restore life.
Any character brought to 0 (or fewer) hit points and then revived will remain in a coma far 1-6 turns. ....
If any creature reaches a state of -6 or greater negative points before being revived, this could indicate scarring or the loss of some member, if you so choose. For example, a character struck by a fireball and then treated when at -9 might have horrible scar tissue on exposed areas of flesh - hands, arms, neck, face.
(DMG p. 82).
I think EGG may have been asked about this one on his Q&A thread and said something about it but I didn't bother noting it and that is quite a haystack to go back through unless this point is a big deal for you. I don't believe it was supportive of your construction.
FWIW, I agree there are different ways this can be construed because unhelpfully the rule is silent on what precisely happens if a single blow brings you to -1 or optionally -4 or less and the language in the first set of brackets is also ambiguous. However, I think that is down to simple oversight that some players would attempt to construe what was being said so narrowly.
The following points are at least equally valid to those you make and in my view have the upper hand of the debate on balance. The rule of course applies to PCs and NPCs so irrespective of interpretation it has balanced application so absent an answer from the rule-maker its a question of table preference. A wise DM asks his players how they would prefer to play since the point of the game is to have collaborative fun in a PvE fashion not barrack room lawyer debates.
1. The silence doesn't of itself expressly indicate a solution either way however if something is not said then implicitly it is
more likely than not never contemplated by the writer. I don't think that helps the construction you are advocating should be implied.
2. The later language and description of hit points being lost up to -6 and -10 and what happens at those points
can be construed as indicating it never occurred to the writer that he needed to do more than just indicate two possible trigger starting points or a trigger starting area where an unconsciousness state would be entered before proceeding on to indicate when you could scar or lose members and then later die no matter which route you came there.
3. Scarring being stipulated as occurring if a creature is brought to -6 hit points is
incongruous with this only occurring by a bleeding or burning method rather than instant physical trauma and with the possibility of death occurring before this negative hit point level. At the very least its
counter-intuitive and thus the earlier death point being implied in here is more likely never intended by the writer nor occurred to him.
4. Further, members severed being stipulated as only occurring when a creature brought to -6 hit points is equally incongruous and counter-intuitive for the same reasons and might also be a strong steer that being brought instantly to -6 hit points, losing a member and falling consciousness was
also in the contemplation of the writer.
5. If the writer had in mind an earlier alternate death point its something you would
normally expect them to expressly mention such a significant thing rather than merely imply it. When creatures die is not something you expect a designer to be deliberately unclear or silent on.
6. Gygax said its the
intent not the letter of the rule that is determinative when construing the rules.
I believe the way it is most commonly played - unconscious if taken to 0, possible scarring and limb loss if taken to -6 and dead only if taken to -10 - is because its the least counter-intuitive interpretation and thus the most likely correct interpretation - not because the community as a whole was trying to contrive interpretations that the language of the rule doesn't bear in order to gain some advantage obviously unintended by the writer, as you postulate.
If anything those advocating the counter-intuitive interpretation of multiple death points seem to me to be the ones with the contrived interpretation of the rule because the introduction of the rule itself was probably not popular with them, for some reason.
The notion you need to hit 0 hit points on a dime in order to enter an unconscious state at all when blow severity is so variable is frankly an absurd and bizarre idea, even as an abstract of reality, which is why no-one I encountered at tables in the UK ever ran it that way. As a DM I wouldn't as I like to keep things simple and intuitive.