I think apple in the last 20 years has mission to be a premium supplier. they just don't see the profit market in higher volume
Apple have
always been a premium supplier. What we've seen in recent years is a push beyond that to become a
luxury, "if you need to ask the price you can't afford it" supplier. Its there in black-and-white in their last few quarters' results - huge revenue growth despite fairly stagnant sales numbers (...and the recent decision to stop publishing sales numbers).
When the iPhone was launched it was completely unlike anything else on the market (and Android took several years to become a credible alternative), so its hard to criticise its $500-$600 price tag. That's why they sold by the shedload.
Now, its 2019. Android has improved beyond recognition, and half-decent, up-to-date, 5" smartphones start at $150-$250. Such products don't stand comparison with the iPhone X when it comes to 3D gaming, VR or serious photography, but for phone, email, navigation, snapshots, music playing etc. they're perfectly good. Today, $500 for a phone
is premium - and for some time, all Apple have been offering in that ball-park (aside from the current, slightly panicky, trade-in deal) is 2-3 year-old models. Effectively, they've stopped making new
smartphones in favour of pocket VR workstations/SLR-replacement cameras that cost
five times as much as a perfectly adequate phone.
Now, I'm no expert on the luxury goods market, but I have a strong suspicion that "mainstream" big-ticket brands (the ones who sell you a pair of factory-made shoes for $1000, not the ones that hand-make a custom-tailored pair of shoes for some undisclosed consideration discretely agreed during your personal audience with the designer) make damned sure that they have a range of branded T-shirts, toiletries or other licensed products at affordable premium prices to (a) bring in the cash and (b) get people hooked on the brand name.
For Apple, where's the modern equivalent of the iPod Shuffle, the $400 Mac Mini or the white plastic MacBook? They're in danger of confining themselves to a slowly shrinking pool of people who are committed to the Apple ecosystem in some way.
Also, other "luxury" products don't need infrastructure - local transport companies, banks, ISPs, streaming media services don't need to produce Apps (or even test their websites) for people with Jimmy Choo shoes. You can carry your company accounts in your designer briefcase even if Louis Vuitton doesn't have a module for UK Corporation Tax rules. A smartphone or computer OS needs a critical mass of users to support its "ecosystem".