For starters, it's Apple the phone making company, Apple the software making company and Apple the (software) distribution company. The cloud, the payment processing, the bank whatever else is there.
They can still be quite integrated, they just have to a allow a different distribution company compete without using the phone company's monopoly as a leverage against them and not use distribution company as a leverage to compete with other software developers i.e. pay the same 30% fee, bid for promotion in the store and use fair ranking in the search.
It's not the first time a huge corp gets split up once they reach end game and can't innovate in their own field anymore.