With amateur radio "dying" as an interesting hobby (my opinion, but widely held) it is often speculated that if encryption was permitted in amateur radio communications, there would be quite a resurgence in interest. I predict a new generation would start to pick up the hobby and find untold uses (and abuses) for it.
Joe Taylor's work on below-the-noise signal extraction has revitalized shortwave: https://physics.princeton.edu/pulsar/k1jt/wsjtx.html , particularly at the nadir of the sunspot cycle. That's a funny sort of dying!
Amateur satellites are accessible for $100 in parts: https://www.n2yo.com/satellites/?c=18 ; with the same parts and some practice and luck you can talk to the space station. That's cool for anyone but especially cool for students; NASA will do more amateur radio work in 2018 than in any previous year. That's a funny sort of dying!
If encryption were permitted on amateur bands, I'd expect to see commercialization right quick—along the same lines as the PACTOR modems embraced by the long-duration recreational sailing community: https://www.cruisingworld.com/staying-connected-at-sea
It's definitely a slowly dying hobby.
I think the bigger issue is noise in urban areas. The FCC does a shit job of regulating noisy equipment. I had to go through my house and dispose of certain Ethernet switches, an audio device, notebook power supply, etc.
Arrow will sell you a great antenna: http://www.arrowantennas.com/arrowii/146-437.html , or you can google "tape measure yagi" and build an okay antenna.
Then you can get the transmitter and receiver together, in a package like the regrettable BaoFeng UV-5R: https://www.amazon.com/BaoFeng-UV-5R-Dual-Radio-Black/dp/B00... . This is a terrible radio. Their quality control is so bad that you sometimes commit a federal offense by pressing the transmit button—and for $100, you can't afford the test equipment to tell! So maybe use it as the receiver in a two-radio setup, and transmit with something like a Wouxun KG-UV9D.
A Kenwood TH-D72A is an excellent choice to do the transmitter and receiver jobs, but hundreds of dollars. A Yaesu FT-60 is a great choice too, but it won't have full duplex—so you can't be sure your signal is getting out without help.
To listen to a satellite you need even less: a crappy antenna and an RTL2832 USB software-designed radio: https://www.adafruit.com/product/1497
For all of these, you'll end up wanting miscellaneous coaxial cable and a bunch of ends. Hams tend to build up a library of crimpers and spare ends and such, so look to borrow from a friend or a club as you get started. The 75 Ω cable that's ubiquitous for television signals will totally work, but you'll have much less loss and much much less stress on components if you buy 50 Ω cable.
Why not try the tutorial at https://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-noaa-weat... ? If that works, you can expand from there: the tutorial teaches you a huge amount about aiming at satellites and the physical work necessary to capture signals from space.
With handhelds being dirt cheap and a yagi cut from a measuring tape being an option, I don't think getting on satellite for $100 sounds undoable.
I apologize for repeating the doom and gloom then, because I know it can be self-fulfilling.
The AARL has optimism but it also tells us net licenses are up <1% per year and "the large number of Baby Boomers will soon be aging off the licensee rolls", predicting "a significant decline in the number of hams, unless we take steps to reverse it." Source: http://www.arrl.org/news/more-than-30-000-new-ham-licensees-...
A decentralized, no-carrier/ISP, disaster-tolerant medium for private communication would be amazing.
I am not a licensed ham so this question is naive: If the major concern of allowing private communication over amateur bands is an influx of private commercial communication, then could bandwidth limits, protocols, signatures (amateur-vs-commercial), and enforcement be worth at least a trial? Perhaps on a new or limited existing band?
A government-run experiment to address demand for this limited public resource seems reasonable.
HAM radio bands are meant for R&D work, learning and basically hobby stuff, not to replace internet or phone services - in fact, the regulations explicitly forbid such use.
That can be done without encryption, though.
Take a look at Broadband-HamNet. It's exactly all these things.
If you are after this (why would otherwise the lack of encryption be a problem for you?) there are both better bands and cheap hw to serve such commercial traffic needs (and, in fact, regulations in many countries explicitly outlaw use of HAM bands for traffic that can be better carried by other services - including the FCC in the USA - so even if crypto was legal, it would still be illegal).
And re amateur radio "dying" - that you don't hear anyone apart from a few old geezers chit chatting on a local repeater doesn't mean it is dying. There is a lot more to HAM radio than this - e.g. stuff like amateur radio satellites, APRS, all that SDR stuff, building digital networks, experiments with radar or even good old HF contesting. Or people simply enjoy building stuff and having the ticket lets them do it legally (some countries don't allow you to own HAM radio equipment without license).
HAM radio is far from dying, just it may not be what you imagine as a HAM radio - a bearded guy in his 60s ragchewing on HF ...
(I am a HAM operator myself)
Abuse would require two licensed amateurs to cooperate to break the law and use the bands for commercial purposes. It would be easier to investigate suspected abuse (compared to unsigned encrypted messages, but not cleartext messages, of course)
Heck, the authorities have problems policing the bands even without having to deal with crypto.