You're missing the point. It's not how much it sells for, or even how much is invested in it. It's the very fact that no matter how many copies are sold, an infinite number still remain. In a working economy, people pay money to overcome competition - essentially the highest bidder mechanism.
With digital products, it isn't competition for the product that drives prices up, but conscience and/or fear of legal recourse, neither of which are really healthy bases on which to establish a market.
Disregarding my later point about value perception (which still applies on the whole, but I'm reducing the concept to simple supply and demand here), you could for example compare a game to a concert performance. With digital, your concert hall is basically of infinite size with infinite performances. The fewer the number of performances, the smaller the audience capacity, the higher the value of a seat ticket.
I've had this argument countered before with the argument that normal market rules don't apply to the digital realm, but those people have never been able to explain why. You can see supply and demand in action when a game is pulled from the Steam storefront and keys are still in free float.
The price that you pay for games is essentially legally-enforced or conscience-based patronage - you pay for games either because you believe that the developer has earned it, or you're worried about breaking the law and the consequences of doing so (there is a third subset out there that argues that you're paying for the ongoing service, which is limited, but that's a difficult one to analyse really). The point is that many people out there don't see value in appeasing their conscience or adhering to the law. This means that for them, the value of a digital product is zero.
My point is not that a game should automatically be priced zero. Not at all. Games cost money to make. My point is that because supply far outstrips demand by a substantial share, all the industry can rely on really is on goodwill and legal compulsion, and that can only go so far until things go really pear-shaped.
Hmm, I can honestly say that I probably still don't get the point.
What is the difference between a manual in printed form and a manual in non-printed form? Both require work to produce and both can be produced in almost infinite amounts (since trees regrow).
To make the story short: I see no differences between retail games and digital games except for the legal status of resellability (which is also completely arbitrary in my eyes). Even a box and a disc - I can produce more of them than there are people on earth, easily, but still the selling price will be much more than just the production costs.
So where comes the premium from? How can people make profit with selling music, movies, books, games, news, ... if in principle the supply is endless and you can copy it over and over.
Of course I never do something illegal, so dragging piracy into the game is just unfair. Piracy is surely putting pressure on prices but that might even be bad in the end and kills devs.
People pay for the value they get, that is entertainment and fun in this case. Producers have to calculate with the costs they have, that is creating the content and a bit for distribution.
Forget about digital or not digital. Forget about infinite supply or not infinite supply. For all practical purposes even the supply of milk is infinite because there are times when there is produced more milk than is consumed still the price does not drop to zero, they rather throw the surplus away (which makes some sense economically).
If people don't want to pay for at least the price it needs to produce something they won't get it and nobody can make it. Maybe this is good, maybe bad. But in the end this is just the free market and it works almost exactly the same for digital goods as for non-digital goods.
So far the free market has ensured that wealth grows and prosperity spreads. But maybe we just make the biggest mistake of our lifes not to pay more for computer games on mobile plattforms - who knows. Shit happens.
I think this is why big publishers engage in the graphics arms race and ballooning budgets that they are killing themselves and the industry's soul and creativity and long-term sustainability with. they're trying to create big enough to punch through all the other draws on money and this is the only way that the people running the show really believe in. Hollywood is doing the same thing with their summer blockbuster movies but movies are still much simpler, tighter, constructs than a game, though.
also, people didn't fork over $40 for zelda and pokemon on gameboy. their parents did.
ultimately it was market research and exploitation that made the mobile market this way and created the culture I guess. now it is that way.
But what will be the future development? As you describe it, it looks like a typical bubble development. It will burst at some point (or has already or will go on quite long without bursting for Hollywood maybe) and then some producers (the best maybe?) will survive and people will start forking over more money again because people will never lose the interest to play computer games.
So it will go on. Bubble, burst, bubble, burst, ...