Mixture is not going to reply, and I don't blame him/her. Whilst I know little about IT, I know a lot about business.
The key bit of analysis of either a sector or a dominant player in a sector, is called "value chain". In that analysis, you look at the final retail price, and move backwards up the design/production/distribution chain to see who is capturing the value in the product.
For a UKP 500 product in the shape of a phone or an i-whatever, someone has captured a lot of value. If (post above) the retailer is only getting 4%, the wholesaler/importer won't be doing much better. The International distributor won't be getting a lot. That is a very competitive sector. We know the products are made by that company-with-suicides in China. They are simply the cheapest assembler in the world. They don't get much of the UKP500.
So where has the value been captured? Apple.
Probably by Licensing arrangements, run through Holland for tax-mixing via BVI for tax minimisation. The USA tax folk can approve whatever licensing rate they want to............and they have always been kind to the nice folk on the West coast.
Don't forget, Apple do not make any "profits" in Europe, and do not pay taxes in Europe.
Compare that with other value chains for £500 items - where often the distributors and distribution chain capture up to 60% or more of the final retail price.
They do not use RPM and they do pay taxes.