Actually Fusion allows to save money and increase profits.
Let's assume Nintendo makes 20 games per year.
That means 20 budgets but only 10 games on the HH and other 10 on the HC - ideally speaking, of course.
Each of those games has it's sales potential cut because it only exists on one Nintendo console.
Now, if you have Fusion in place, even assuming that Nintendo only made 15 games per year, each console would have 15 games per year.
That means that despite having less games, you spend less money on game budgets and you manage to not only increase the number of games per system, you also increase it's sales potential.
I think it's safe to assume that most people neither buy two (Nintendo) consoles, neither do gamers buy a system for just any game.
With Fusion you garantee that even small or "medium" sized games can sell well enough, but you also create a bigger market for all the developers who support Nintendo.
In the end you do increase your revenue with 1st party and 3rd party games.