They might recognize Flynn's name, but he wasn't getting much reporting in the press anymore, he was losing most of his bouts, so he wasn't getting much financial support either. You are not earning much money on a semi-permanent loser. The fight was held in Salt Lake City suburb. Dempsey was a local fighter, who was thought favorably by local press and local fans, he had a good winning streak, so it's quite natural that he would be getting enough support in his native area against an outsider. If you read the IBRO article, you should be aware, that Dempsey didn't always stick to facts and truth, so his stories about being very poor should be taken with a pinch of salt. The same article mentions some of his purses from that time, they aren't bad at all.
To outslug and outphysical a Dempsey/marciano.......You have to be a george foreman. David Tua was no george foreman.
The way I look at it is that you need an absolutely granite chin and huge power to outslug Tua. Ibeabuchi had a great chin, but I don't think Dempsey's was of the right calibre. Dempsey had big power, sure...but I don't think he was as powerful as many do, and even if he did, does anyone think that he can reasonably expect to stop Tua? Tua's shutout UD loss to Lewis is totally irrelevant in this matchup. Dempsey is not 6'6 and 240someodd pounds and he fights nothing like Lennox. I seriously doubt that he had Lewis' power, too, but, as I said above, I don't think Jack is going to be knocking Tua out. It's basic styles make fights. In a come-forward slugfest, I'll put my money on the guy that's 40lb heavier, has the better chin, and punches harder...every time. It's not like Tua is a slug, either - he had a major problem with long jabs, but he can throw an amazing amount of punches when his target stands in front of him, like we can expect Dempsey to do. There's always the chance that Dempsey tries to outbox Tua, but does he have the jab, size, and style to do what Lennox Lewis did?
I don't think Louis or Tyson would stop Tua either. Tua isn't getting stopped unless it's on cuts. The guy who got KO'd by Flynn in 1, punched out of the ring by Firpo, and floored by Tunney? Even if he has better defence, he has a very suspect chin. Does it really matter if he circles Tua, though? As long as he's coming in, he's coming in. Tua had problems with negative fighters in Lewis and Ibeabuchi, both of which are bigger than he is and a great deal bigger than Dempsey. Dempsey is nothing like Byrd. If we're going to play this game, we can say that Tua has the size to do what Willie Meehan did.
Those nine knockdowns were when Dempsey was an undersized, malnurished, teenage hobo, no bearing on the quality of his chin. Dempsey fought plenty of decent punchers. Firpo scored a couple of knockdowns, but he never kept Dempsey down for long, Willard got in a couple of shots that didn't seem to phase Dempsey. Dempsey went through fights with Carl Morris, Gunboat Smith and Bill Brennan without ever being in trouble, all of whom were thought of as hard punchers at the time. He took everything Jack Sharkey had to offer over 7 rounds when he was past his prime. The fact is that Dempsey, in his prime, was only knocked down in one fight.
My point (among others) was that Morris, Smith and Brennan don't compare to any of the punchers that other ATG's like Ali, Louis, Marciano, Holmes, Tyson, Lewis, Holyfield, Frazier, etc had to dael with. You say "the best Sharkey had for 7 rounds". Sharkey was not a big puncher at all, unless you qualify someone with a KO percentage of little over 20% as such.
Apart from a left hook and a sturdy will, what did Frazier have? Apparantly it was enough to beat the #1 heavyweight of all time.