Watched the 1st 2 episodes so far, here are my thoughts...
From a personal point of view it's interesting to see the development (and failure) of Ploom...
I remember receiving promotional emails from Ploom back in the day (circa 2010), and I thought "why are you trying to sell a butane powered device that requires proprietary tobacco pods (in a few flavours) when you can use an e-cig instead?"
I did find it vaguely interesting (though never tried it), thought it looked smart, but was a device like that was ultimately behind the curve (due to e-cigs)...
Anyway, (according to the documentary) it turned out to be flawed, but I presume paved the way for other Heat-Not-Burn devices, which are now very popular in other countries, but never caught on in the UK (or not yet).
Now, as for Juul itself, more than once in the documentary, people are saying there was nothing available between a puny cigalike and a large RBA type (with technical knowledge required)...
This is of course a load of BS...
The Janty eGo (with Dura-C old style refillable cartridges) was brought out at the beginning of 2010, with the eGo-C (refillable with liquid in a chamber) following a year later in 2011. Although considered at the time a "large" 650mAh capacity (compared to ciggielikes), the eGo battery was still small (followed by an even smaller 350mAh version). The Evod (coil changeable) followed in 2013.
So, there had of course been smaller (but not puny) devices around for many years before the Juul came out in 2015 (and they had the advantage that they were not proprietary pre-filled pod devices either).
Now, they may not have had the same design aesthetic as the Juul (memory stick image), but Juul essentially became popular for 2 other reasons, the invention of nicotine salt (so the 50mg required for Juul was not too harsh), and luck. (Both of which confirmed by the documentary.)
The trendy marketing to youth was of course ill-advised.
Anyway, still interesting to watch, and I look forward to the last 2 episodes...