At the risk of being a contrarian, Apple's focus on being a consumer-product company is deeply rooted from the beginning. You could argue its focus on UI since the beginning of OS X was for consumers rather than developers.

Microsoft is a famously developer-friendly company (sorry, "developers, developers, developers," comes to mind). However during Ballmer-era years, user experience was jumpy, and developers had free reign to build their products even if it was disconnected from the OS look and feel. The transition to Windows UAC, for example, was a result of Microsoft being too lax on developers for many years before (writing to anywhere on C drive), until Microsoft said they couldn't just write to anywhere.

Apple has been restrictive to developers, and that has been the way with Steve Jobs. They've locked down many APIs (even abruptly deprecated them) and punished apps that don't conform to Apple's consistent look and feel. So in that sense, Apple may not be the friendliest to developers, but it has pushed a more consistent product. Perhaps these restrictions are why Apple's products give all users a good experience despite more annoyances to the developer.