I see 'streaming video on mobile devices' as another tech bubble that will burst sooner than most people think it will. There is only so much bandwidth available, and people keep demanding more and more of it, and all the while wireless providers like AT&T and Verison are literally gouging people for service,
Except "streaming video on mobile devices" does NOT imply that people are using their cellular data plans at all. The linked article even talks about people using free business/municipal WiFi.
I see it either coming to a point where you can't get more people and more bandwidth because it just doesn't exist, or it getting to the point where people are paying so much money that they start backing away from it
I don't see that happening... Spectrum reuse (smaller towers, lower-power antennas, with much shorter range) will allow the existing available cellular frequencies to be utilized many times more efficiently, blanketing small areas (neighborhoods) with much higher speeds, which don't interfere with the big towers covering large geographic areas.
The up-coming FCC incentive auction will give the cellular companies big new swaths of lower frequencies. Meanwhile micro-cells and pico-cells are decreasing in price and increasing in popularity with cellular carriers, and their operation necessarily involves higher spectrum reuse. LTE-U operates just like WiFi, on the same unlicensed frequencies and with a very small radius of service, and those devices should be available very shortly.
Meanwhile there are people like me (and I don't believe I'm anything like alone in this) who have no smartphone and see no reason to ever get one, because of how much wireless companies gouge for 'data plans'
You're not alone, but certainly in a very, very tiny minority. Back in early 2013, the majority of all Americans owned smartphones, and that trend has only increased several percent per year:
Early 2015: "overall smartphone penetration up to 77% of mobile phone owners in the U.S. Among recent phone acquirers, 91% chose smartphones as their mobile handset [...] Overall smartphone penetration continues to rise rapidly, increasing 8 percentage points"
While there's some truth to what you say about the two biggest US cellular carriers, it doesn't apply to T-Mobile/Sprint.
T-Mobile now offers unlimited video streaming (Netflix, HBO NOW, Hulu, more) that doesn't apply against your data allowance. And that's besides T-Mobile offering "unlimited" data plans for some time.
Sprint doesn't charge overages at all... they prefer to throttle your data connection down to much slower speeds, rather than disconnect your data, or charge you extra fees. And a Sprint service like Boost with several GBytes of data is just $30/mo, including most taxes/fees.
MVNOs can have even better deals. RingPlus, FreedomPop and others offer free plans that include cellular data. Some MVNOs like Republic will allow activating your smartphone for $10 with unlimited calling/sms, but NO DATA PLAN at all. You are tied to WiFi for internet, but that means no overage charges, ever.