Reading some ScroogeMcDuck comics coincidentally after reading Daisy Miller got me wondering — Could John D. Rockerduck's popularity in Europe somehow be related to the traditional "old money vs. new money" conflict between old European and American values? Glomgold may be a dishonest Corrupt Corporate Executive, but he is a Self-Made Man like Scrooge. Scrooge's conflict with someone who inherited his fortune like Rockerduck might be more significant to Europeans. Or I could just be far too presumptuous.
I think you're reading far to much into that. In fact, I, even though I'm an European, prefer 'self-made men'. Times changed, I do not believe that the Europeans still (if they ever did as a whole group) find someone who inherited his fortune more important. ('Cept maybe the English.)
What's funny is you got thing the wrong way around. Sure, Rockerduck inherited his money while Scrooge is a self-made man, but most modern depictions of their rivalry are rather around the lines of Rockerduck as a modern businessman who gets money from investments, buys yachts and high-tech gadgets, is all about fashion and the picture people are getting from him, in fact acting more like a real-life present-day billionaire, whereas Scrooge is an "old-fashioned" billionaire who keeps his money in the form of cash, sits on it, is stingy, made his money "square" with "his bare hands" and doesn't care about the opinion people have of him as long as it's not an obstacle to him winning money. Rockerduck incarnates modernity with all its wasting, its pointless vanity and its smugness, while Scrooge is the incarnation of "good old times" where public opinion wasn't a big deal and people made their money with their bare hands, and then kept their money without boasting about it. In a nutshell, paradoxically, Rockerduck's more the "new money" and Scrooge the "old money", in another meaning of those two words.
Don Rosa writing a Kalevala-themed adventure for the Ducks was highly appropriate. As the comic says, Elias Lönnrot wrote the The Kalevala by compiling various Finnish myths, legends, and poetry together — exactly what Don Rosa did with The Life and Times of Scrooge McDuck. It's a fitting reminder of how all the great epics were written, from 700 B.C. to 1992.
In real life, Scrooge would've run out of business quickly. His workers and families will quickly figured that working for ANYONE else will bring much more money and less headaches. Or worse, he will go to jail sooner or later when someone sued him for pay his workers at much more lower than minimum wage. However, since he owned nearly any kind of company (from resorts to oil refinery), he can get away with it since he contributed so much to taxes and people lives that he's practically invincible to law, and people who starved for job will still work with him anyway. The effect is showed in some of Don Rosa and Carl Barks's comics, where Scrooge's showed as the only man in Duckburg that able to pay things like Rocket Project and giant robot's production cost.
On the other hand, he pays so little to Donald... because it's time off for him. He doesn't consider it 'real work', he simply covers the time lost by Donald when on treasure hunts, but since Scrooge is an explorer, he also considers the treasure hunt to be a reward in itself... Or at least this is what he'd tell Donald!
Scrooge pays little, but he pays well enough and makes sure his workers won't need much more money thanks to side benefits.
It's pretty much shown time and again that Scrooge owns nearly every business in Duckburg. So there's not really any getting around working for him. Only difference is that some people work directly under him within his Money Bin and others work far away at one of the various businesses he owns.
Why is Rockerduck so obsessed with defeating Scrooge? Two reasons: the first is that he usually comes as the second richest by very little but he also spends more, and given his standard insult to Scrooge is pointing out he's a tightwad the fact he's less rich because he's not as much as a skintflint obviously burns; the other is that Rockerduck's own father taught Scrooge how to be a prospector, and he most likely knows (he had all the elements to guess it. All he needs to do is to check the records for the name of the prospector who staked a claim to the Anaconda Copper Mine...).