Yes, there's a full machine-learning stack you can buy. Has auto-mapping, heuristics, active listening, voice commands, and can easily move from room to room. Also equipped with weapons platform to deter people who shouldn't be there.

A dog.

It depends on what one means by "garbage", but I've found that hard-wired systems (i.e. wires for all sensors) backed by something like the standard Honeywell Ademco Vista series attached to a real cellular uplink works most reliably. We use them at home and at business, and for what a home security system is supposed to do (make noise when an intrusion occurs and send a signal out so that you know about it) its the most reliable setup I've ever used. (Not to mention, provides a ton of options for "hacking" your system to your needs.)

Just, whatever you do, do NOT let some crazy internet-connected service, like XFinity Home hook up to it. All of your reliability goes out the window the second they hook up their stupid takeover devices.

I do not believe so. Perhaps commerical grade stuff? But in the consumer space, it is all overpriced and "bad."

But consumer electronics are generally insecure: garage doors, baby monitors, electronic door locks, even cars historically.

They all ultimately rely on security through obscurity because convenience sells. Nobody wants their garage to lock them out because the clocks got misaligned, or firmware update the clicker because the encryption protocol from the 1990s is trivially broken.

Frequency hopping would be more common, but many consumer electronics only utilise two frequencies because that is all that is allocated. So that is out. And while they could use fixed key encryption (e.g. serial number), it doesn't defend against a replay attack (and if defence is added, like a counter, it can break the system in a number of fun ways (e.g. batteries running out, signals being lost, cross-device interference, etc)).

I did a lot of research on this a while back and concluded that, no, there don't appear to be. I was hoping that Nest, despite some of their shortcomings, would try to tackle this market. Seemed like a more obvious market for them to move into, as opposed to smoke alarms.

You could make one. A bunch of ESP8266 modules connecting back to a rasberrypi via SSL with a strict sensor timeout would mitigate the comcast alarm style bypasses. As for a remote, key fobs are so 1990s! Connect your smart phone using an app.

Ta-da! A custom alarm system that doesnt suck.