I would be the last to argue that you're wrong, in the sense that what is immersive for different players is likely different, and you've always been quite consistent and articulated your position on this kind of thing in a way that feels genuine.
For me, it is a bit different. See, we were playing AD&D, and we were playing it for a LONG time, like 10 years at least, and what we discovered was that you'd create a new PC (the 493rd one probably by now) and cursorily write down your 'stuff' (after rolling for gold) from an equipment table we'd utterly memorized (boots, high hard 5sp...). Now, 22 months later, your character is 8th level and his sheet has been transferred 3 times (because a hole got worn where you write your hit points).
Heh. For just this reason we track our hit points on a different scrap of paper, or on the chalkboard.
His gear is now stuffed on some back corner written in dull pencil (dull because this was the last thing you moved from the old sheet). Maybe now and then someone remembered to scratch out something that got broken or used up, but mostly the last 14 times you were in town you just mumbled something about 'gearing up' and probably didn't bother to reduce your 14,904 gp by 136sp for replacement stuff (nobody is quite sure, was it 5 or 7 iron spikes).
The main reason I have to re-do character sheets is that the possessions lists (both magical and mundane) get so messed up that I can't find anything any more.
That said, at high level when we're rolling in money, with the DM's approval I'll just knock off a generous amount (considerably more than the book costs would add up to) and re-load the mundane gear; the extra money goes as tips and gratuities to the smiths/vendors/etc. If my character happens to be short of funds I'll pull out the book and track it much more closely.
Frankly, my character is an almost-name-level bad-assed dungeon crawler. I'm much more immersed in the character when I think "yeah, he's geared up, of course I've got flint and steel in my small belt pouch (3cp)." We invented, more informally than anything else, something like the kind of system DitV uses. It was just more immersive. When you got to the sloping rotating trick room/corridor thingy then of course Doug the Delver had 10 iron spikes and a 3' piece of chain in his backpack to use to bugger up the mechanism. There might not have been an exact number of times you could narrate this sort of preparedness, but don't overdo it and things are good.
If the DM was a bit dubious about a specific instance, maybe Douggy had to make a WIS check to see if he actually thought of having 3 colors of chalk or not. TO US, this much better emulated the sort of super prepared and vastly experienced types we imagined playing.
We're pretty strict in saying "if it's not on your character sheet, you don't have it", largely because we've had issues with certain players in the past who either a) gamed the system a bit too much or b) would never otherwise bother to record anything and then just shrug when asked whether they had some specific piece of gear on hand (usually, for some reason, this always seemed to arise when the party needed a grappling hook).
Side story: tracking mundane equipment did directly lead to one of our long-standing gaming memes, that being "never carry a collapsible shovel".
This came about because in a long-ago game (1988-ish?) some player/character decides that having a collapsible shovel in the backpack is a fine idea, and so buys one while in town...and in the next adventure that PC dies at the first possible opportunity. Party loots the corpse, someone finds the shovel and says "Hey, I'll take this!". Then that PC gets killed in the very next combat. Loot the corpse, someone else takes the shovel and...you can see this coming, can't ya?...that PC doesn't live out the day either, butchered by some monster or other.
Then someone realizes that the only common denominator is the shovel. "It's cursed! It's cursed!" they cry, and ritually bury the thing. And wouldn't you know it, no more PC deaths for the rest of the trip!
All of this was due, of course, to sheer luck of the dice...the shovel was never anything more than a bland boring collapsible shovel with no enchantment or curse of any kind on it...but it made for some great entertainment!