I've actually been wondering about this topic, recently, myself.
I have some Dionaea that have skipped one or two deeply cold dormancy periods, so far. They're all indoors, and the light has been 18/6 throughout, but the temperature drops 10-20F in the coldest days of winter (compared to the hottest days of summer), and the humidity drops significantly, as well. That said, I don't believe the temperature ever drops below 50F (58F was the lowest surface temperature that I recorded with my IR thermometer), and the light has exactly as intense every day. I don't remember what happened last year, but this year, the plants that grow both tall and low leaves based on the season, switched to their winter forms, and are just now switching back into their summer forms.
All but one, are thriving. I am going to attempt to feed them, this year.
This makes me believe that Dionaea don't require a long, near-freezing dormancy period, to undergo metabolic changes according to the seasons. I am not sure what would happen if they didn't get any form of environmental changes, at all.