Apple is playing with fire, they have built an incredible platform for others to build on top of, but a platform requires a level of trust from developers and businesses in order for them to invest in it. Apple seems to be doing their best to destroy that trust. What Apple's greed seems to blind them to is that while, yes, companies gain a lot by building on Apple's platform, Apple also accrues a lot of benefits just by those apps existing, without having to take a 30% cut.