Cobb Vanth had been a marshall cleaning up the area for at least a little while. He had garnered a reputation.
Boba Fett tracked quarry when there was no such thing (in any SW medium I'm aware of - films, books, comics, etc.) as a tracking fob that locates based on DNA. So this is a guy who knew how to track and find whatever he wanted to. A bounty hunter who can make a living tracking across an entire galaxy is someone who shouldn't have any problem getting information he needs to find the location of whatever he's looking for.
And yet again, I'll point out that he had access to his ship. It's hard for me to believe that he wouldn't know where to go for the right leads. He would've spent plenty of time on Tatooine because Jabba was a source of requesting his services. He had obvious encounters with at least one Tusken (hence the rifle and gaffi stick). He had knowledge about procuring resources to get Fennec healed up with cybernetics. This is not a dude who is going to be clueless. Especially if he's been wandering that familiar planet (with his ship available to him) for any length of time stretching beyond just days or weeks.
This is a guy who wore braided Wookie scalps over his shoulder as trophies. So being ruthless in getting what he wants shouldn't be a problem either.
True.
But IMO it doesn't take into account the mess a Sarlacc gut might have made of you
. So, OK, there's the bacta spray/solution. Even then, Boba's face looks messed up. I'd assume the rest of him looks the same - scars, burn scars. So that's time the Jawas find the armor, and trundle away.
So Boba's got the ship, and his skill set, but u have a set of armor at minimum is deep inside a pretty big vehicle, and there's plenty electronic chatter to derail even the most sophisticated scanning. Dunno but maybe event the Jawas have some sort of anti-scanning re the vehicle. Also there's probably more than one clan of Jawas trundling around Tatooine - they are like fleas, or something. Lots of them.
There's more time gone dealing with Fennec. And yeah, Vanth has a reputation, but it's probably pretty local. So Boba's in the area - but unlike Din D'jarin, does he sit down and chat with them? So that leaves hanging around a suspicious small backwater town, maybe. More time gone.
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Since there are not a lot of (any) specific time details - how long did it take a wounded Boba needed to crawl from a pit (he more or less describes himself as one of the wretched, cast aside), heal, and start tracking? - I'm not seeing an issue here.
If anything, *realistically* - this is a guy that survived a Sarlacc and survived a brutal aftermath is incredible - e.g. did he get help? Doesn't sound like it. Sounds more like he crawled to his ship - maybe - and had to treat himself (kind of like Din D'jarin did, but obviously 100X worse). Crawled or stumbled across &^%$ sand, and deserts get freezing at night. For miles. Maybe it took more than one day. Maybe with your own tissues hanging off you from acid burns. Oh, yeah, a lot of minerals have a salt compound. That must have been fun, getting that into open wounds.
Then there's the Empire collapse and everything goes to *&^$, on Tatooine as well. For all we know, Boba had to fight off desert raiders and scavengers, more than once. Tusken Raiders, too.
We also don't know how long Vanth was in the desert (days?). We can assume Vanth cleaned the town out pretty fast, but this town sounds like a blip anyway. So it'd take a while for ANY news of this armored sheriff to filter anywhere. The Mechanic sez "it's there, or at least it used to be". We're not talking a major settlement here. It's some Tatooine backwater.
I just don't see anything ruining Boba's mythology, *realistically*. Unless it's intolerable re the lore (dunno) that this guy 1) could be badly, badly hurt and battle back and 2) that the guy might have some sense of honor, instead of just shooting Din D'jarin and going FU, I got mine.
Especially when by default, the man's had several years, at least, to be alone with his thoughts. NOT hunting bounties. His armor matters, tho, after all that time. Why? Technically speaking, he doesn't need it to survive. But it matters to him, either as a point of honor or because it was his father's.
For me, a one-note character isn't very interesting, after a while. U know what they are going to do, EVERY TIME. Instead looks like Boba is gonna be a kind of anti-hero instead of a (apparently) a stone cold sociopath or victim of child abuse who is still getting even. (And can't comment about any book/comic portrayals).
It may not be what long-term Boba fans want, but IMO it's an effective portrayal.
That's just brutal. 
He was so bad I almost missed Jake Lloyd. Almost. What made it even worse was Lucas doubling down on him in TCW. That really tested my crapola tolerance level.
