It's one of the biggest and wealthiest companies in the world, but your comment seems to imply they have to pick and choose what they pursue. They really don't, especially if it's hard- vs software.
Money can often just be one part of the equation.
To do things well you also need - available & capable technical resource, suitable facilities, available & capable leadership and management (with engaging at the right level in the business) and a clear vision of what you're trying to achieve/working towards.
Given how Apple appears to operate, I wonder if a strong desire for senior management control/oversight over major developments means they (artificially) limit how many concurrent large-scale things they can work on at any given time?
Maybe not, but that'd be my guess.
I didn't imply, it's explicit in my comment. it's what their actions show. Their updates make their systems worse and worse, Tim Cook is out and Siri is in shambles. It might have been something else, but I'm willing to give it the benefit of the doubt, because the alternative is just sheer stupidity.