Garmin and Magellan use NavTeq (which Garmin bought out)
A correction: Garmin never bought/owned Navteq. Garmin and Navteq shared data layers, the extent of their partnership. Philips sold Navteq as an acquisition to Nokia a decade ago, and now Navteq is part of the HERE entity that is owned by the Audi/Daimler/BMW consortium.
Again, untrue. Apple likely has no control over the data streaming into their app.
Apple does not own the data stream.
Not entirely correct in perspective. I've been in this business for about 25 years, presenting to my clients and managers. Think of what you see in Apple Maps as a flattened AutoCAD/Photoshop/Illustrator file in appearance, layered over a searchable series of data sets - that's what is presented to us.
What goes into that "presentation" is definitely up to Apple. When I buy a SHAPE file subscription from an agency - just like Apple would - I can enable/disable hundreds of data types using a control panel. Building on this, in some areas we will find overlap in area coverage - TomTom's Tele Atlas, MapBox, Navteq, Verizon's MapQuest will try to sell me mapping data, POI's, GIS data, and more - and it's literally a bidding war by those companies to sell me their data and attract customers to the information that they pay for. I have to factor the accuracy of that data, often by sending a survey crew out to verify survey monuments. I may use Navteq in Portland and MapBox in Wahkiakum County - and I have to verify everything (something Apple/Google/Verizon/MS definitely would get fired for not doing if they worked in my company!) Apple absolutely pits data providers against each other - I see a typo in Maps that exists only in Mapquest in one area and a misaligned roadway that exists only in Navteq in another area but they're both in Maps, and knowing the surveyors and GIS techs gives me a bit more insight here than most Maps users.
Those SHAPE files are not cheap. And, if I need an aerial it's likely another $15k cost for my client, just for a localized area and not an entire geographical area. Mr. SID aerial TIFF files aren't cheap…
My point here is that Apple picks and chooses data they want to display, generally based on cost and general interest in an area. They enable layers at different zoom levels. They tag aerial data and their 3D images depending on zoom and perspective.
Wherever Apple is getting their data now, I'm hoping that the Apple Mapping Vehicle that drove past my house 2 weeks ago (in NW CT, not in a major city) will mean that is changing, and soon.
Don't hold your breath. Look up Skamokawa WA, I'll wait. An Apple vehicle drove by a friend's B&B in October 2015. She wanted her B&B in every iPhone. I told her to not hold her breath - geotagging takes a massive effort and plenty of time. I created an entry for her with Apple and told her to create an account with Yelp and TripAdvisor, and how her B&B has those two review/recommendation portals tagged to Maps.
A MS Bing vehicle preceded Apple by about 6 weeks. MS has had those street view and geotagged bits online for about 8 months, and they're using their own mapping data to supplement them (they were found in their Maps Preview but they're widely available now on Windows and Windows Phone (I use a Lumia 640 too) and their mapping in the US and Canada on Windows platforms posterizes Apple and Google (BB fan here…). Bing Maps blows chunks two ways - on iOS they use Apple Maps as a base and their aerials in the PNW are ancient.
Why doesn't Apple in particular, with its rabid fan base, do a "user updated" Map model (with heavy Apple oversight) a la Waze??
Money. The cost of base mapping is still ludicrously expensive - my budget for a 7 county area runs $100k every year for subscriptions, I don't own any of it and I have to mail the last-quarter data back to the agencies. The cost of potential liability is expensive - I shed tears when I write my liability insurance check every quarter - and Apple gets to "foist" the liability of accuracy to the mapping data owners when, not if, accidents occur.
Google spent billions on HD satellites (which they just sold a few months ago) for aerial data and likely tens of millions on drivers and the cars they were in. I'm seeing newer aerials from Apple Maps
for iOS only in my area in 2D view but not in 3D view (August 2011 aerials, I know who consigned them) or in the macOS app AND those newer aerials are different than the local "reseller" is offering in their paid-for offerings, which leads me to surmise that Apple has consigned their own aerials from a satellite imaging company (I just checked my GIS SHAPE file and compared it to the local agency ("reseller") and they are indeed different. I can offer that those images I'm seeing now, with the detail I'm seeing, were not cheap.
It's basically money and liability. I have engineers and surveyors working for me, people with lots of experience - and I still redline drawings every single day - there's no way I would use a "crowdsourced" map and expect complete accuracy. I check DOT cameras before I leave a location as I've learned to not trust those little green lines. I call ahead to make sure a restaurant is still in business - snow and ice here put dozens of small businesses out of business this past year, but they're still in Apple/Google Maps. I still carry a newer Thomas Guide with me everywhere I go - I know they're right and the Guide doesn't need an internet connection!