I think that for most of these carnivorous plants the real mitigating factor is probably sunlight. I have tried experimenting with growing various genus' either in terrariums (with and without lights), on windowsills, outside and in greenhouses. Here in SE Alaska, lower night time temperatures are never an issue, humidity is never an issue BUT available light IS an issue. A D. capensis or N. ventricosa can survive on a naturally lit windowsill here and survive, but it will barely grow and only pitcher or look somewhat healthy in the summer. With a little artificial lighting it seems that MOST carnivorous plants will grow just fine anywhere you put them. (within reason).
As a terrarium grower I have constantly heard people say, "no you can't grow that plant in a terrarium for any extended amount of time as it will quickly out grow your enclosure." I have found that for the majority of Nepenthes species (especially), that this is just not true. The plants can stay quite small and quite manageable for several years. Though, if you wish to see them flower they will need to move on eventually, but for most people, a couple of years isn't really a short amount of time. Very vigorous Nepenthes hybrids WILL usually outgrow terrariums within a year or several months though, that is true.
On the other end of the spectrum - it blows my mind that there are people that can't keep plants alive at all, considering how forgiving most plant species really are.