Yes. You and I are on the same page here. Many of my comments were based on the presumptions put forth by
@HammerMan who said that adventurers will have 10-50k in gold by 5th level(yeah, right) and/or retire as 3rd level spellcasters and get rich off of selling magic items. Under the presumption most adventurers are retired very early and there would be a surplus of created magic items and few remaining adventurers to buy them.
I think most people with reliable financial sense are probably not going off to adventure in the first place.
Many others have personal goals that will be met by spending the money in various ways such as I described, so they're not necessarily examples of foolish spending.
Not foolish if you have the means. My point is, if a guy with $5 million decides to build a $4.5 million luxury yacht, and has no reliable source of income, you wouldn't call him 'wise'. Sure, if he's got a $1 billion and regularly rakes in more, there's no such thing as foolish. You were using all these huge expenses to explain why adventurers are broke though, and I would just pointing out that the smart ones hoard their money and maybe invest in a nice potion shop...
And I don't really see why its not feasible for adventurers to normally only get 50gp for selling a potion, but the retail price of 100gp makes selling them profitable, albeit the market may be small. If said adventurer joins the Alchemy Guild (good luck with that) then he can get the needed license, and of course he'll need to rent a stall at the market (contracts run for a year, 500gp up front) etc. Well, now we know why Joe the Blade just sells his surplus potions for 50gp each... OTOH if he wants to retire and make money as a potion master, what's the issue? I never understood why that had to be somehow decreed a bad thing by the GM. No doubt Joe becomes an NPC at that point, or there's a LONG interlude in his adventuring career, whatever. At the end of that interlude he's slightly wealthier than before, but most of it is sunk into stuff that isn't very fungible, like his alchemy license and marketplace lease.
Anyway, we agree, it isn't that easy to just 'get rich', OTOH if you have some mad skills like potion brewing or spell casting, that might do it. I've always favored the sort of logic that says there really aren't adventurer types wandering around. Yeah, there may be a few NPC specialist guys that can do some of the same stuff, in their niche area, but your wizard is pretty much THE wizard, at least in most regions. Perhaps if he goes to the mythical Island of High Wizardry he'll be just some schmuck, but in his home town? Nope, he's that one guy who can cast a spell, pretty much... (there's that witch down the road, but don't look at her teeth too closely, or go near her place after dark).