Burns, Jeffries and Johnson were busy champions. Willard had WW1 to deal with which put the sport on a backburner (tho he wasn't much of a boxer at heart and preferred rodeo work)... So, the trend was there to be busier. You have to go back to the days of Corbett, Fitz and Sullivan to really find the guys who turned so heavily toward the stage or traveling shows as champ. In regards to the legality issue in the US, Johnson won the title in Australia, defended it in Paris and lost it in Cuba. There were other options.
Jeffries and Jonnson were only marginally more active than Dempsey. All champions before Dempsey took the title on the road no different than Dempsey just a different venue.
Jeffries boxed 9 times in 6 calender years. Dempsey boxed 6 times in 7 calender years. Jeffries boxed 1.5 defences a year, Dempsey boxed .8 defences a year, or .1 shy of double. Post their winning the title - that's a huge difference.
Jeff defended his title seven times. Most historians do not count his 4 round bouts with Kennedy and Griffin as anything more than exhibitions. As mentioned not very different from Dempsey. All took their title on the road... Exhibitions, stage and with Dempsey Hollywood.
When you say "most historians" do not count his bouts with Kennedy and Grffin as more that exhibitions, who are you referring to specifically?
Any noted historian. I don't keep a tally of those I have read. The Griffin bout was for only 4 rounds and Griffin had incentive to last the distance rather than go all out to win. Kennedy bout again for 4 rounds and he was Jeffries sparring partner.
Fleischer for one. He was closer to these bouts than anyone in terms of historians. His Record books show these as exhibitions/not defenses of his title.
Any bout where an incentive is given the challenger to last the distance cannot be a true defense. Logically.
What did Dumb Dan Morgan say about it? I don't think they were defences. But I know Griffin wasn't any exhibition. But you seem to be claiming Dan Morgan and Nat Fleischer claimed it was an exhibition? Is this correct?
You are saying you know they were not defenses? So why are you counting them as defenses when you try calculating years vs defenses comparing Jeffries and Dempsey??