For example, "The Cave" is $5 on the Apple Store but $15 on the Wii U. I was just wondering if the game is actually of much better quality on the Wii U or if it's just a way to get more money. 

Many other games are priced like this as well. 

Have an answer?

Are you really asking about expensive games on Nintendo consoles?? Really??

Nintendo doesn't believe in price cuts.

Yes I am. I thought this was obvious based on my opening post but I guess not.

care to actually answer my question?

Sony and MS are no different.

It will be a long time before games on the console networks are as cheap as Steam, Google Play, Apple, etc etc.

The answer to your question is Wii U owners have nowhere else to go for games than the eShop.

tel me about it i had a 20 gift card and got an Old school mario game for $7.99 !!!! thats crazy IMO

It is the same price for the PS3 as well. For this game at least.

In the case of Nintendo games...well it's Nintendo, Mario Galaxy is still $50 in my country, and I know is similar in the U.S

As for 3rd party and indie games, well I guess they are taking advantage of the Eshop. I mean if Nintendo doesn't drop their prices, why should them? You can find some deals from time to time though, most indie games were $5 during the holidays, and big games were $20-$30 cheaper. 

Steam games usually have the same prices as retail, the difference is that their deals are so freaking good that no sane person buys games at the normal price.

The Cave is still $15 on Steam so yeah. It's $5 on iOS because iOS reacts badly to most games over $5