We have centralized services for a lot of reasons, but one of them is that they're more reliable than decentralized systems. Phones get lost, stolen, drowned, and crushed. People drive through tunnels or into mountains without cell signal. Batteries die.
It seems patently absurd to think that a P2P network of handsets is somehow going to replace The Datacenter, on any timescale.
If the cloud is just a supplementary resource where you back up or distribute opaque, encrypted files, or crunch an occasional workload, for a moderate fee, you could have your reliability without the lockin. I think mesh networking might be nice for a handful of applications, but it isn't even the core of the issue here: it's about whether your computers are glorified dumb terminals for someone else's computer, or whether your computers are machines that can function as islands when they need to.
That said, your personal communication will be stored on the servers encrypted if you use encrypted chat like Whatsapp or Telegram.
I am not sure why you had to use cloud server when sending files over LAN. I've uploaded videos directly to iOS over ftp server, and Android has tons of apps to sync data back and forth, all locally.
I am not sure why your TODO list needs a central server -- Simplenote does not require login, and it totally happy to keep everything locally. There are integrated note apps as well.
So to summarize: everything is there already. But people prefer to choose a simple solution and use cloud-based service, instead of doing a little bit of work and creating "machines which can function as islands"
That's the experience we have right now, with centralized servers. With a P2P system the experience is: My sister sees that I uploaded a new picture, tries to click on it, and gets some opaque timeout error because unbeknownst to her I drove into a tunnel. Depending on whether or not my phone is destroyed in an accident before I emerge, she may never see the picture.
Unreliable distributed systems look intermittently and unpredictably broken to users.
Google said in 2011 that a single Google search uses about 0.3Wh of power. A typical mobile phone battery has a capacity of about 12Wh. Peer-to-peer systems are almost always less efficient than client-server systems, often by a large factor. You do the math as to whether a peer-to-peer internet based on mobile phones is even remotely viable.
https://www.nytimes.com/2011/09/09/technology/google-details...
Isn't this an argument for more locally hosted services?
Have you noticed that each and every piece of the web has its antiparticle?
The original web was the browser with links and simple graphical presentation, some server scripts and SQL databases. Then we've had single page applications in which links lead nowhere, nosql, serverless. This is like extreme serverless or webless.
If you can think of another basic web element, you can invent some new anti-paradigm that will be loved, hated and discussed endlessly over here.
[1] https://pdos.csail.mit.edu/papers/grid:mobicom01/paper.pdf
In practice who knows what kind of communication patterns you would get. Applications would probably evolve around the long distance limit if it existed, but it's hard to imagine not having backbone links. Most likely the meshes would stay relatively localized (and I believe there exist a number of regional wireless mesh networks out there serving real customers).
900MHz in US is 902-928 MHz, 26 MHz wide channel. The usual SNR ratio range is 0-40 dB. This corresponds to total bandwith over entire band of 26 to 172 Mbit/sec -- depending on the range. Let's be generous and say 100 Mbit/sec.
You are not going to get any sort of beanforming from the mobile pocket-held device, so your collision domain is going to be everyone around you. Say you are in the park, and there are 24 people around you, and you are all routing packets for each other, so each packet is transmitted twice before leaving the collision domain. In this case, single person's ideal, best case bandwith is 2 Mbit/sec.
In practice, you are not going to get anywhere close to 100% efficiency, so I'd expect internet speeds significantly less that 1 Mbit/sec. This is going to be very painful.