Bruce Wayne's Dad was an Arms Dealer
I'm watching Batman Begins, and right away we know that Brucey Boy comes from money. We know his parents own people, we know his house has its own postal code, and we find out his dad privately funded a municipal rail system because poor people are people, too. This is the kind of money that smells like old leather money.
But where did that money come from? Pappy Wayne tells us he spends his days at a hospital, and that the skyscraper downtown with his monogram on it is just where other people make him money. He simply comes from money.
Bullshit.
Big Daddy Wayne seems like a decent human being. He acknowledges that the lower class exists. He stands places in public near vagrants. Deliberately! He seems to have ethics in raiding his child. We never see him feeding an offending peasant into a wood chipper. The guy has decency, and you know why? Because rich fuckers have no souls.
Look at the Trumps. Look at the Cardassians. Look at fucking Paris Hilton. People rich enough to dominate a skyline are assholes. These people do not comprehend the idea of "a job". They do charity work because they'll never need to have make a car payment. Bruce Wayne is First Generation "I Grew Up With A Trust Fund". Daddy earned his money the hard way.
Now what is the Hard Way? Clearly it's profitable. Having your name 50 feet tall letters downtown permanently requires a significant financial support structure. Daddy Wayne looks like he's in his 30s or 40s, though, so it had to come Fast as well. There are few industries where money is volitile enough to get that rich that fast. If Pops were in finance he wouldn't be a remotely human being, because even if they're not rich yet, they don't know it. What other industry could be so prodigiously profitable? Well let's look modern Wayne Enterprises for clues.
We know Wayne Enterprises is at least tangentially working with the US Military. This company got government contracts to construct a military weapon system. They US government does not sign weapons contracts with finance companies. It doesn't have software development companies built them rocket powered tanks. There was a reason Lucius Fox was sitting on all that next level kit that out performs military grade gear. It's because this is the company making the shit that all the soldiers are running around in.
Companies don't typically change industries, though. Not without a big reason. We've already established that Big Daddy Wayne grew up at least middle class, though. That means he is likely the man who built the company and probably wouldn't have steered the company away from what made it wildly successful in the first place. So they must have been building fucking Knightrider tanks back in the eighties when Pops was building Bruce's inheritance.
Bruce Wayne's father made the family fortune manufacturing and selling arms and weapons systems. That's where the money comes from. That's why Wayne Enterprises built the dangling subway right up to their front door. As a premiere supplier of the military industrial complex, they probably are one of the largest employers in the city.
Note that Bruce's dad never says he works for the hospital, just that he "spends his time" at the hospital. He could be running a public charity out of a rented office at the hospital, Alfred Nobel style.
My point is that Iron Man is totally a better character than Batman. Tony Stark owned that his daddy sold weapons. He was up front and transparent about it, and when the time came, he owned that shit and changed what his company sold. Bruce Wayne hides that, though. Owning a man servant? Buying estates over disturbingly cave riddled land that no genuinely rich person would ride living on? No. Bruce Wayne ignores his family legacy to play rich boy whack a mole. Tony Stark did what he had to to make things right.
Plus, if you use all the money in the world to do anything besides inventing rocket boots, you're doing it wrong.
Sincerely, Doctor Science Pothead