It's not free to design or sell, even if the audio parts used "have the capability". If Apple thought they'd sell more phones, they'd do it.
Back when I was fighting the good fight against Apple, MP3 player vendors kept adding FM (and eventually HD Radio) in the hope that it was what Apple users were missing... The radio industry liked that strategy too.
>It's not free to design or sell, even if the audio parts used "have the capability". //
The chances are that the system was designed to enable it and the choice to disable was made commercially. It seems most likely to be like hardware with more memory or faster clock speeds where the manufacturer just cripples it to make the cheaper model.
Ugh, this has always been a terrible idea - apparently a vanity project by people who know nothing about how manufacturing works.
Every piece they make modular adds cost - cost of connectors, weight of the frame to support them, cost of support when the connectors fail.
You can go on about "waste" all you want, but the lowest cost, lowest material devices are rated for single-insertion connections along with components both stacked and heavily integrated.
The reason they could not do displays, RAM, etc is that these components are tightly integrated to the SOC selected, and change regularly. This was true when they announced, even more true now.
Truly Google is the new Microsoft if they devote such time to obvious executive vanity projects, untouched by the taint of reality.
All those costs in modularity apply to PCs, which are still around despite the hard drive to turn everything into a SOC. If I were able to get the same amount of use out of a modular phone as I have my daily driver PC (going on nearly 10 years) then I'd happily pay more for the robust design. I get that the popular justification for SOC is power savings, but the cost is so much higher than just incredibly rapid obsolescence. Consider all the software problems, the binary blobs, the lack of security updates, the vendor lock in... we really need to step off this crazy train.
Right, because we all know the most important feature of smart phones is their cost savings, which is why Apple phones sell close to their marginal cost and don't have 30% margins.
And this kind of device, while it may not be interesting for many consumers, will be very interested for industrial, enterprise, or medical users.
With bluetooth you need to consider radio interference between the sensor and the main device. In my experience that increases complexity of the sensor, and is something you largely can avoid with a module that has a physical interface to the main device.
I'm hoping that project Ara will become the perfect test bed for sensor module development. Useful after the initial validation stage of experimental stuff on a breadboard but before the stage where you have established enough customers that you can afford to develop a completely integrated and standalone IOT device.
There are lots of mobile devices specifically designed for industrial and commercial use. Usually they are much more expensive, but add few additional components. It would be useful to be able to build up your own devices from standalone components. But I doubt it is really in the interest of the manufacturers who want to be able to offer a complete "solution".
zakalwe2000 mentioned a lot of kinds of costs; you only mention the monetary one. In fact, your example of the iphone supports his/her point - a non-removable battery improves reliability and makes phones slimmer & lighter while also more mechanically durable.
Not everyone values slimness to an extreme, and despite the fact that non-removable batteries improve certain design margins, many many Android phones still have removable batteries, and some even reverted from non-removable designs to removable ones.
There is a crossover point wherein overhead reduction is "good enough" and when other factors about the phones begin to dominate.
The iPhone doesn't sell because of a non-removable battery, and the huge number of users who use bulky cases to protect fragile phones, and add-on battery cases, which increase weight and spoil the industrial design, tend to support the case that some people are willing to trade off thinness, weight, or cost for other capabilities.
I don't even think this is controversial. If you look at the number of users asking for microSD whenever a device removes it, or the people wanting additional clip-on lenses, there's a hunger to extend the phone platform.
Now, whether that happens over an integrated UniPro bus, an external lighting cable + case, or bluetooth, is an implementation detail of convenience, ergonomics, and bulk. I personally would rather have upgradeable camera modules or additional battery slots than "Morphie" cases and weird protruding clip ons that weren't designed to work with the builtin optics.
More Space. New Ideas.
The Ara frame contains the CPU, GPU, antennas, sensors, battery and display, freeing up more room for hardware in each module. We are looking to module makers to create technology never before seen on smartphones.
With 3D printers, cheaper cheapsets, ..., tinkerers can go on and try to create their own module which they can integrate into their phone. If the module is popular amongst users, integrate it either as a standard module in the ARA store (a 3rd party could for example propose to manufacture that module, shifting those costs to them, Google would just deliver the core ARA product).
There's worse problems at a lower level - hardware caches on the disk do not really guarantee flushes are honored either. There's a discussion of this here - honoring writes is an enterprise feature... http://serverfault.com/questions/460864/safety-of-write-cach...
