While I agree with the total number of items likely found KD, I'm not sure i agree with your assumption of the spread of items. Yes, strictly by the list, you might be right, but, let's be honest, there are a number of items that parties will find, like +1 Weapons or +1 Shields, which are likely going to be a lot more commonly placed by DM's than, say, Eyes of the Eagle. I'd say it's a pretty rare DM who strictly randomly generated magic items and never deviates from die rolls.
After all, it's common to put magic items on "Boss" monsters, which will tend to be weapons, armour or the like. I'm going by personal experience here, which, I realise is not broadly applicable, but, in our 5e Dragonlance campaign, which has now hit about 9th level, we have only a couple attunement items and our LMoP campaign which, is 3rd level, and has found exactly 1 (the glass staff) attunement item. I'm not sure where you are getting all these attunement items from LMoP. We certainly never found them. Granted, I'm a player in both campaigns, so, maybe we missed a lot, but, I don't think so.
Summoning [MENTION=2067]Kamikaze Midget[/MENTION] for commentary on Lost Mines of Phandelver.
If you reread my post, I was also talking about total magic items (i.e. 1 magic item per level), not just attunement ones. I just used the attunment DMG ratio to illustrate the point. In LMoP, there are something like 10 non-consumable items in a module that is designed to go to level 5. That's more than one per level per 4 PC group (where 4 items should be found gaining 4 levels).
+1 Longsword
Staff of Defense
Ring Protection
+1 Battleaxe
Boots of Striding and Springing
Spider Staff
Gauntlets of Ogre Power
+1 Mace “Lightbringer”
+1 Breastplate “Dragonguard”
Wand of Magic Missiles
I suspect that many tables that use LMoP will have quite a few of these items in a party if the DM plays the module straight up.
Btw, I agree with you on the boss item thing. I do that all of the time as a DM.
But in our 6th level campaign, there are easily 10+ attunement items in the group of 7 PCs, and probably 15 or more non-consumable magic items total. Everyone has at least one and most have two and some have three. Some because the previous DM handed out quite a few magic items, some because of modules like LMoP (where I as DM handed out Lightbring and Dragonguard because I thought they were cool). I only DMed just shy of 2 levels and I handed out about 5 or 6 magic items in that time frame (about 10 gaming sessions).