You wanted to know what idea you had I found the dumbest? A button to encrypt your phone on the fly. Why you think this should be a thing escapes me. Even in brain storming you give an idea quick sniff test before committing it.
You thought that one was stupid? I thought that was at least decent. You made me do a google search to see if it exists, and searching for a hardware switch to lock down your phone and encrypt your calls and messages (on top of what is already encrypted obviously) brings up this:
http://www.theverge.com/2016/5/31/11818358/sirin-labs-solarin-privacy-smartphone-hands-on-photosIt looks like an awful phone (16000 for a shitty Android phone?) but there's no denying that's a neat feature. Being able to lock down your phone with hardware may not be useful to people like us. To the makers of the Blackphone and their customers, however, they might want to take notice.
You don't seem to understand the term "Mature technology". There isn't really anywhere for the technology to go or space to innovate. You keep asking for the next dumb-phone to smart phone explosion, but that isn't going to happen again for the foreseeable future unless someone figures out how to make a Futurerama EyePhone. At that point phones become obsolete and you're talking abut transhumanisim.
Again...I gave an example of a space you could innovate in now. We have the technology to split our phones in two today; the guts and the display. The potential for following this idea is extraordinary. I could have several configurations of screens to choose from, selecting and switching on the fly, yet my phone stays the same. I could break or lose my screen, yet still have my phone. I could borrow someone else's screen, pair it with my phone, and have all of my information present. I could send out the same information to multiple screens with my one phone. I could control multiple screens at once. And it goes on and on.
To take one of your examples, if you could shrink a mass spectrometer down to something that was phone size that would be a great thing for the scientific community, but it would be a worthless feature to build into a phone. Such a thing would be an accessory or a dedicated device as Joe Public would have no reason to ever use such a thing.
Okay, weird example, but I'll use it. If we could shrink down a mass spectrometer to 1/32 of the phone size, then we should include it. Joe the Public (why are you hating on the public?) may not find an immediate use for it, but a clever developer coupled the spectrometer with the camera and made a real-life pokedex capable of telling you what you're looking at with greater specificity and what it's made out of. Genius.
The point is, while these features may sound ridiculous to you, the fact is if everyone had it, the amount of information you could receive and use is incredibly beneficial. Let's again take the barometer for example. Because it's built into every iPhone since the 6 (and several lines of Androids), it allowed a developer to create a real-time, crowd-sourced weather forecasting application that gives you very accurate data based on your exact location. You can know when the rain will start and stop down to the minute on you specifically.
Second in line is the squeeze phone. There is no way you're not going to accidentally squeeze too hard activating something. Also we already have a far better solution called buttons, you know, the ones on the side of your phone.
Again, you fail to see the usefulness in this space because of an inability to look past current hardware features.
Putting pressure on a phone is very different from squeezing it, especially if the phone can learn where you're most likely to place your fingers and how hard you can squeeze. Furthermore, different actions can arise by where I squeeze, how many fingers I use to squeeze, and if I'm squeezing with my left or right hand. Please explain to me how a button can provide this level of sensory input?
Third, I guess you never heard of bluetooth ear pieces.. invented back at least the year 2000.
And that's why you see them everywhere, right?
People can't be bothered with them at the moment. And still, holding up a phone to your ear for long conversations is tedious. Most people opt to have their headphones on in those situations or use their speaker-phone setting. I'm offering a third solution, place an earpiece in the phone itself. The speaker and microphone don't need to be great, only functional. What's more important is that it needs to be immediately accessible. I suggest you search 'tiniest bluetooth earpiece'. I think you'd be surprised by how many people would be excited by this feature.
As I said before, all the companies are looking for some sort of feature to sell to the market. If they think it is viable and useful to you they would include it into a phone. No matter how big your brainstorm is they have had 1000's of people doing the same thing and actually built it in a prototype or already pushed out as a product.
And that product is an iPhone 7. Obviously, something is wrong here.