What you're describing focuses too much on the implementation on a specific platform. It's true that each vendor will provide their own way of doing things (perfectly normal), and things will change as well (also expected). But you have to also keep in mind that there is a lot that can be learned about the Bluetooth protocol and technology itself that is independent of the platform its implemented on. If the developer does not understand the protocol and specification, then they will end up getting sucked into the implementation of the specific platform.
I don't work for Nordic nor have any affiliation with them, but from my experience, their support is top-notch and I love the community interaction and support they offer through their DevZone site. No vendor is perfect, so it goes without saying that there will always be pros and cons.
Believe me, I stick with Nordic, and I think they stand the best chance at success. My overall point is that the system is basically at the point where it is nearly impossible to be a generalist, and very painful to be a specialist. So whats left?
The release of SDKs, and softdevices, and silicon are accelerating. If you are supporting customers on SDK12, who have heard about the shiny new features of SDK14, by the time you've signed the contract to do the migration, Nordic is imminently releasing SDK16. Forget the odd numbers in between.
I literally put my foot down with one of my fellow developers about a year ago, because we kept wasting 30 minutes everytime we'd discuss some bug, because he'd be referring to SD132v2, SDK11, NRF52832, but since I was developing for a client that day who prefered SD132v3 SDK12 NRF52832, I kept saying "dude, I promise you that bug does not exist", while he keeps screaming "bro, I've got the breakpoint hit right now!!!".
Our solution was to standardize all of our conversations, by first saying, 52-132v3-12 has this bug, yadda, yadda. And that worked great for a couple of months, until Nordic decided to release a better product, the nrf52840, but couldn't find enough courage to make a unique name for it.
So, I predict that in the very near future, Universities everywhere will make Linear Algebra and Deep Learning prerequisites for Introduction to C and Embedded. Because thats the only way you'll ever stay ahead of anything for more than an instruction cycle.
First, a disclaimer that I'm the author of the e-book listed.
Yes, I agree that getting BLE to work with smartphones is not an easy task. The APIs are ever-changing and evolving and differ across different devices as well. In the end, though, they must adhere to the official specification and provide an interface to the underlying protocol.
There are many embedded developers that are looking to learn the protocol and don't know where to start (myself included, especially when I first starting learning the technology). The specification is quite overwhelming and there is a lack of resources that cover both theory and implementation together.
The book is targeted at embedded developers with the goal to help them learn the basics of the technology by guiding them through various exercises and examples. There are also many new use cases popping up where an embedded platform is used on both ends making the task easier (compared to pairing with a smartphone app).
