I was never interested in any Reality Show and still don't (Shark Tank seems kind of interesting though :-).
If I have to tell why I am guessing it must be because they are unrelatable to me (maybe because of my cultural background).
But first what would make a reality show better than others?
I think number of viewers would be a good measure and that is ultimately what TV producers would care about, isn't it?
Then what would be the best bet to get more viewers?
Find something almost everybody can relate to!
If so then wouldn't you say that if you really find such an idea it could be the biggest reality show ever?
Here is my idea to offer a candidate:
I think almost everybody in the world sometime(s) in their lives thought that
"Look at that rich guy(s) keep making tons of money!
If that was me I could do even better!
"But dang it I didn't born rich and I never have nowhere near enough money to make the investments I want!"
But what if a rich guy came to you and said (gasp!)
"Put you money where your mouth is! (nah!) Here is N million dollars!
I give you N week(s)/month(s)/year(s?)!
Until the end of that time, you tell me how to invest this money (buy/sell anything anytime)
but you just need to make sure, by the end of your given time, all money is back in the same currency as it started!
Let us see if you are really the great investor you always claimed to be!"
For adaptation to a reality show, imagine you (the TV producer),
selected N contestants any way you want,
put them in a Big Brother style house that has no communication to outside,
and made all or each of them the same offer as above!
And you let the whole country/world watch how things really went and turned out in the end!
(So everyone can take lesson(s) for themselves!)