I know back in the days, in the USA, I used to classify CULT films (not all) as films that have well known actors (again, not all are like this) that goes under the radar across movie go'ers esp the mainstream. Then it hits home video ... more people see it, talk about it, following and viewership grows ... During this growing time it gets more widely acclaimed as a cult film. As its like a cult phenomenon that it grew legs and started to become popular. Some tell tell signs are merchandise then comes about after X time because the popularity has grown to support it where as said merch didnt exist before unlike big blockbuster movies where merch is either out before theatrical release, during, or really shortly after.
I'm old enough to remember being the main movie goer in my group of friends that I had to recommend this film to family and friends who knew nothing of it at the time. Everyone enjoyed it. Has it aged well? That can be debated.
I think what can make some people not consider a film cult is when the popularity of the film grows so big that they think its just another hollywood movie. It doesnt take away the history, and shouldnt no longer let the film enjoy their cult status just because it did well enough to become a big time movie so to speak. They deserve both. Drive is not quite yet a "big time movie" but its cult following is growing, tho there is normal masses that would like V much better then Drive as I read a lot of casual movie go'ers who crap on Drive as "there is hardly any talking". Pulp Fiction is still a cult classic, but with Tarantino's popularity and it being one of if not the best overall movies in his library, some new folks find it hard to say its cult ... its just Tarantino.
V was cult for a long while in the USA ... due to its representation in the world (the mask) used more at protests then say Halloween ... I'd say its cult. However in the movie nerd world, it can feel more like just another bigger than norm catalog title in the vast library that is Warner at times.
Still deserves its due, whether that is a good movie,or a cult classic to each their own.
And yes I know that there is a whole other class of Cult films that star B-list actors, Indy directors, and/or actors first roles before stardom. While not fitting all those, Boondock Saints quickly comes to mind as it was a very unknown film and was very fun to show to people unbeknownst. I've had some of the same joys over the years here being initiated into a lot of UK films I had no clue of. Same could be said of Asian films, like Oldboy and Battle Royale.