How would Tommy Loughran's career go in the current era?

Cool story but it was well known that Loughran drew the color line.

 

Several articles from throughout Loughran's career referred to him drawing the color line. Most blatant example was when he ducked Tiger Flowers. Loughran's people claimed that he would fight Flowers in private but as far as I can tell, they reneged on their offer when Flowers and his manager called their bluff. Flowers died later that year.

"With the Scrappers," Wilkes-Barre Times-Leader Evening News, Oct. 5, 1927:
“Tex Richard and other big time promoters have tried to match Flowers and Loughran, but the former Philadelphian draws the color line and has turned down several big offers to meet the Georgia Deacon. When some of the sports experts said that Loughran feared Flowers, Joe Smith Tommy’s manager made this statement: “Loughran has drawn the color line but…”


Loughran also refused to fight then-contender Joe Louis because he was black.

“Tommy Draws Color Line”, Semi-Weekly Spokesman-Review, Sept. 10, 1936:

“Declaring he wouldn’t fight a negro unless the world’s championship is at stake, Tommy Loughran declined an offer of $35,000 and 27.5 per cent of the gate receipts to fight Joe Louis, Detroit negro, in Philadelphia October 12.”

 

Good find, but I wonder what the source of that information is and how accurate it is. It's inconsistent with counts I've seen elsewhere and it'sstrange that there seems to be no record at all of several of his alleged early fights, since he was already getting a lot of attention back then due to his unprecedented size, his well-known manager, and the growing interest in the juggernaut division.

 

None of this is "evidence" that Impellettiere had "a lot more" fights. And I don't get the basis for your claim that the default assumption should be that there are likely missing fights.

Some of your specific assumptions seem reasonable but I think they're off the mark here.
I ended up wasting time going down a Ray Impellettiere wormhole last night, so I'm going to share some of the info I found. I can try to post article excerpts some time, but it's probably not worth the effort.

A little bit of backdrop on Impellettiere's early career might help. He was discovered at a very young age and groomed for years by his manager/hype man, Harry Lenny, a prominent and well-positioned boxing insider. Lenny spent years getting him in shape (had to lose a lot of weight and build up his unusually skinny neck, apparently) and teaching him how to box. Lenny was talking him up as a future champion and trying to position him to take on Carnera and the other guys in the (subsequently-aborted) juggernaut division before he even debuted. The Imp got a decent amount of attention, including some brief regional newspaper writeups well before he fought his first professional match. Lenny deliberately brought him along very slowly and carefully controlled his development though, because he had big hopes for him. Impel wasn't some tough street kid taking sketchy backroom fights for $20 or barnstorming against small-town palookas.

Lenny talked Impellettiere's way into the title eliminator, and it was considered a major coup given that the fighter was so inexperienced and untested. I have an article on that somewhere...

All that being said, there are a few articles that list Impellettiere as having had more fights than are listed on boxrec (the number varies from article to article though and they never identify any of the opponents though). I've also seen articles listing him as having fewer fights than are listed on boxrec (allegedly because Lenny left some of them off of Impellettiere's official record because the opponents were of such embarrassingly poor quality). But the newspapers still captured these bouts nonetheless, and it's not clear why we would assume that many others exist. And again, any undocumented fights that did exist were likely against absolute no-hopers. Impellettiere did not work his way up through the rankings.

So it seems possible that: (a) Impel had a few undocumented professional fights against absolute no-hopers during the first two years of his career; (b) some writers along the way got their facts wrong, perhaps because people were giving them bad information; or (c) the missing fights were actually exhibitions or something.

 

There is no reason to believe that Loughran went back and forth on the issue.