Well, you have your "I am absolutely right and cannot be refuted" idea of what 1e rules are, but legions of players didn't agree with your interpretation, lets just leave it at that. You can try to dismiss them all, but you will never overcome the sheer murkiness of the AD&D rules (especially 1e, but 2e is pretty unclear as well). It is probably not worth rehashing this argument, though in brief many groups simply interpreted TWF in 1e to mean you got one extra attack PER ROUND. This is perfectly consistent with D&DG, Drow, etc. Yes, Roger Moore is in your camp, and nobody disputes that was a common interpretation, just that it is FAR from the only one!
You dismiss the optimization value of TWF in the original rules under your interpretation (or even our more limited one except at high levels). DEX is not the dump off stat for fighters which you make it out to be, if you take a really sophisticated view of things. We played vast numbers of hours of 1e, probably several thousand hours before 1980 even (I played every day at a club that had 100's of players from 1977 to 1980). So we may have been a bit unusual in our level of focus on the rules, but still...
DEX will get you out of trouble a lot better than CON will, unless you are a dwarf (obviously). It adds to your AC, and thus effectively to a lot of situations where you'd need to avoid poison and other nastiness. It can also apply in a lot of uncodified situations. So it is a really good defensive stat, and avoiding damage is better than a CON bonus, certainly a lot better at lower levels.
And then we come to OFFENSE. First of all, missile fire is greatly superior to melee. Not always available, but when the other guy cannot hurt you back, and you can move and retreat easily, its gold. DEX improves your missile fire (later 'strength bows' became a thing, which allowed STR to add a damage bonus, assuming your DM allowed them, though they were a bit expensive and most magic bows don't have that attribute). So there is that, plus the reaction adjustment, meaning you get to STRIKE FIRST most of the time with a high DEX. This is also gold, a dead guy cannot hurt you, make him dead before he even gets a swing, gold.
Now, think about TWF. That extra attack, granted it is a d6 weapon, is still effective. With an 18 in DEX it is barely penalized at all. So, yeah, an 18/nn% STR is pretty tempting, but gauntlets are a thing, and not super rare, plus there's that nn% role, which is often low (1-50% is all the same bonus). Unless you role better than 50% an extra attack for d6 will give you about the same DPR. Yes, you don't get your +1 for shield (sometimes) to AC, but you DO get an AC bonus, which is not limited to 1-3 attacks from a certain angle per round. So, are you really giving up much by putting that 18 in DEX?
You mention shields and magic shields. Again, good for SOME situations, but there's always another PC in the party who can use it just as well as you can. I never encountered the "shield like peanut shells" thing, magic shields were a thing, you would be likely to get one at some point. Also magic armor, rings, bracers, cloaks, etc. which are all things that showed up at some degree of frequency and can grant similar bonuses. So, yes, you personally MIGHT be giving up a bit of AC (usually 1 point in my experience) but you already GAINED up to 4 points!
And there certainly are magical daggers and hand axes, though perhaps less common than magical longswords, sure. However, you can still wield the magical longsword! The dagger/axe is in the off hand anyway. Sure, there may be a situation where it isn't worth using against some large creature, maybe, though that is pretty situational.
I would note that my Ranger, a completely 1e character, has Gauntlets of Ogre Power, and wields a highly magical bastard sword in one hand, and a magical hand axe in the other, and indeed has an 18 DEX (and a magical longbow/some magic arrows too). It is a classic optimization, and the character was stupid deadly, which is the only way you survived in the murder hole that was most of the campaign. Heck, the whole character's main characterization was wiping out the Demogorgon cultists who murderized all the other members of his first party. I think that character was sole survivor of SEVERAL wipe outs. We never missed a beat on optimization, for sure.
Of course, you could go the high CON or high STR route also, or be stupid fortunate and have 2 or 3 high stats and have your cake and eat it too. STR at least is the only one where there are items to increase it. I won't really disagree that STR as the high stat is the obvious choice, and a good one. CON is more of a nice thing for dwarves or at high levels where the +3 or +4 (yeah, how often) can stack up a whole bunch. Low level PCs don't really gain much from a CON bonus. DEX I've already outlined. In our understanding of the rules DEX was pretty much the 'god stat' not STR or CON!
So, for the rest, you are right, UA borked things good. If you used Weapon Specialization then TWF went from a pretty good optimization for say 50% of fighters and all thieves and some wizards, to ridiculously optimum. You could cancel out most of the TWF penalty with DEX, and then build on top of that, AND your missile attack rate increased too! It was broken, just like ALL of UA, all broken. Doesn't even take the silly 9d6 method to make it broken, its just broken.
So, yeah, 2e absolutely clarified the rules and set a fixed, and lesser, increased attack rate for TWF. Given that it still incorporated most of the Specialization rule, TWF was still really good. In fact overall I think it is still better in 2e than in 1e, and given the relaxation of the restrictions on off-hand weapon, that much better. 2e hand axe machine guns are definitely a thing, though I think that level of specialization is a bit limiting overall and probably more of a trick build.
