.... Now for poor people to all of a sudden come into wealth, that looks fishy.
I am pretty sure the time line will show that for the 4 men in question.
Your analogy of Poor Young Tom then 30 years later is pretty much every ones story. Most people take years to build up to .....
AAaahhh, good move Stretch

So my push- back, is met with a counter push-back. And I must say: Yours is an ingenious push-back. It acknowledges mine as true (that poor to eventual affluent doesn't mean "treasure"). So then, in order to wriggle around this truth, we must enter another factor : The speed-to-which a person ascended to that position.
If it's through hard work and business, sure, you're right: Not likely to happen overnight. And sure, no "stock markets" or "lottery tickets" back then, that could have accounted for it. And regular work/business results = too slow.
So : For everything you're saying to be true, we have a SLEW of "devil in the details" to have to be accepted as premises, or dismissed as not applying :
a) We have to go back to some historical record proof of eventual wealth (tax filing statements ? etc...). I mean, is this "salacious details" even true, IN THE FIRST PLACE ? And no, I would not accept the "legend" as proof of this. Because that would merely be "pointing to the legend" as "proof of the legend" (circular).
Don't forget: If someone conjectures 150 yrs. ago that
"It has been said that McGinnis was suddenly wealthy". Then here's what happens next: 30 or 40 yrs. later, at the next telling of that tidbit: the
"It has been said ..." part of that sentence, gets dropped. The "suddenly wealthy" part is all that rings true, and thus: The legend evolves. Hence I'd want to see some corroborating original substantiated evidence, aside from just "pointing at the legend".
b) this wealth would have to be "sudden", as you yourself say. If the "proof" just shows he died affluent, or that years later, he "passed out cool old coins", then .... that lacks the proof of "sudden".
c) And there *could* be other ways to come into sudden wealth back then : Inheritance is a main way. Theft is another way. Etc...
Thus for your proof of "someone probably found the treasure", to rest on the "sudden wealth" of the individuals in the legend, you've got a LOT of closing of loose ends to do. But I admit: That was a genius move to show that the Tom_in_CA story wouldn't hold merit, if we added in the key word "sudden".