It's a completely shared infrastructure from the demarc in your home to the local cable node. It's not very secure and pretty trivial to abuse. Remember this was an infrastructure originally implemented to distribute TV signal.
Because of that TV heritage and the way they grew (on a town by town franchise basis), cable networks were usually a patchwork of really shitty networks up until fairly recently. My (limited) understanding is that on relatively modern cable systems, there is fiber connectivity to the local nodes, and then coax from that device to the homes in the area.
DSL is a switched network of sorts, and provisioning happens on the switch in the CO. Ditto for fiber.
Google thinks bebop is better than whatever they could do internally (including finding people to hire up) to build a comparable product for that budget.
This is Yodlee, the USA's largest financial API for consumer products (Mint, etc), endorsed by all large banks and investment firms. They have millions of users.
You don't need much bandwidth. The Internet is creating a false sense of data size because nowadays even a simple hello world seems to require a multi-megabyte download. But actual communication for practical purposes can be done in just bytes. There's more than enough space in transfer title to communicate a lot of stuff, even without a pre-arranged set of shortcuts, and in planning stages, you don't need real-time communication anyway.
(Note, this comment would fit in one or two bank tranfers).
'Disorder' will always be a nebulous concept because it's an abstraction that encapsulates a dissatisfaction with the fitness of a person's psychological complexion in the context of the person's environment. Hyperactivity and a short attention span might be a disorder for a student who must focus deeply on a single concept, but an advantage for a hunter-gatherer who must integrate a large number of shallow ideas simultaneously. Thus I will humbly refrain from taking a strong stance on your questions; I can imagine situations in which each would be advantageous and in others the opposite.