I'm not upset about it because I consider it like this: if the manga is a comedy, just like you said, it's campy and fun, playing the trope for the gags. If it's a serious manga and they give a 20 year old a worldwide company without having any regard for realism whatsoever, I blame it on a lazy author and badly written plot. I told my friend this reminded me of Christian Grey, who's a millionaire that has "business" and nothing specified. But that's bad writing, so, skip it and on to the next. Or laugh, which is also a good option.
I guess it depends on how much you are willing to go through suspension of disbelief to enjoy the plot. ╮( ̄▽ ̄)╭
What about all the rich guys in yaoi? And I don't mean just rich, I mean most manga incorporate at least one ridiculously wealthy (sometimes he is a prince as a bonus or a yakuza). Well, they are nice once in a while, but come on, how can you sympathize with all the extremes? Putting realistic elements can make it more interesting some times. I mean look at Usagi-san from Junjou. His family is wealthy and he is extremely intelligent and still became a lazy but extremely good author who earns millions... COME ON! And this is acceptable, since Junjou is a comedy, where exaggerations make it cute.... But there are other mangas, that try to be more mature and seriously, extremely wealthy people do NOT go along with realism. What do you guys/girls think?