They could increase their cut. But they could also just increase the price per app, by reducing competition (e.g. only allowing 1 app of each sort). They would be incentivised to do this, to make more profit, obviously.
Seeing as games are being discussed, Nintendo used to do this by increasing the manufacturing cost they charged to make the cartridges (afair, Nintendo had a stranglehold on the cart manufacture), and hence you got situations like where Street Fighter 2 on the SNES was crazily priced - don't remember exactly, but something like £60 in the UK.
>Much like iTunes, they're happy to leverage this huge library of "media" to boost sales of devices.
If they had a device monopoly, they would no longer need the apps to be cheap to boost device sales, which is my point.
Are they going to increase their cut? Doubt it. Why would they? Apps are not what makes them money: devices are - and they make a lot more money from having a healthy app ecosystem than they do from squeezing every penny out of developers.
Of course, Apple's ways are mysterious and unpredictable. But they have so far shown no interest in increasing their cut of app revenues. Much like iTunes, they're happy to leverage this huge library of "media" to boost sales of devices.