Marketing jargon is great at twisting the definition of simple words. A blockbuster film used to be a play or a film that was massively popular and financially successful, such as "Jaws" or "Star Wars." Of course, since there were no strict definitions of what a blockbuster was, soon advertisers started referring to all big films as blockbusters, then all films that were expected to be big as blockbusters. Nowadays, they usually refer to movies that have large studio-funded budgets, like most of the summer franchise films.
Then we have the word classic, which used to mean an older favorite that stood the test of time and was still popular with contemporary viewers. Think "The Wizard of Oz," "It's a Wonderful Life," and "The Ten Commandments." In the hands of DVD and Blu-ray hawkers, a classic is any older film, whether well-regarded or not. On Netflix, "Classic" designates films of a certain age. Of course some have tried to apply the term to newer films too. "A new family classic!" is a common line of totally oxymoronic advertising copy. Disney used to release everything on video as a "Walt Disney Classic," including all of their new releases. They can get away with it, I think, since Disney is awfully good about maintaining their legacy films and making sure they stick around in circulation forever.
But for many film fans, I've noticed, the term "classic" still manages to retain loftier connotations, and you'll occasionally see debates about what the criteria should be. How old does a film have to be before you can start slapping on the moniker? How popular does it have to be to be regarded as a real classic instead of a cult classic? Does box office matter? Does name recognition? How about influence and historical/cultural value? It's funny that you rarely see anyone ask whether a classic film has to be any good or not, because the presumption is that a film that is still remembered and beloved after a certain span of years by so many people must be good. And that brings us to "Twilight."
People, mostly female, love the "Twilight" books and movies. Other people, of both genders, hate and revile them. To date, I still haven't seen more than the occasional trailer or television commercial for the film series, which launched with the first "Twilight" in 2008, so I'm not taking sides. However, it's plain that these movies are massively successful and profitable, have been very influential on the popular culture, and they're going to be remembered in years to come by a whole generation of girls and women. It's premature to call "Twilight" a classic yet, but by all indications it stands a very good chance of being one in the future, especially if it manages to work its magic again on up-and-coming young audiences.
"But it's a terrible movie!" the naysayers rage. And yes, it probably is, but that doesn't make a difference in the long run. "Dr. No" is a fairly tame thriller, but it retains its place in history and movie lovers' hearts because it was the first James Bond movie. I thought "Jason and the Argonauts" was a bore, except for those fantastic Ray Harryhausen special effects sequences that have gotten so much press over the years. And have you seen the original "Star Wars" lately? I love that film as much as anyone else, but I have to agree with more critical viewers who point out the stiff acting, dodgy effects, and crummy science. Time has a tendency of making people forget or be more forgiving of the bad bits.
As someone who watches a lot of older films, I'm continually astonished at the kind of mediocre stuff that gets so much attention, while better quality titles languish in obscurity. Shirley Temple and Busby Berkeley have been immortalized, but no one save the academics and the film geeks like me think much of mostly forgotten directors like Victor Sjöström and Erich von Stroheim - both probably better known to the general public for acting performances than the masterpieces they directed. So it's probably inevitable that "Twilight" and "Transformers" and their ilk are going to be what most people will look back on fondly in seventy or eighty years, while the more prestigious, less accessible films become even more niche than they are now. Quality doesn't have a thing to do with it, and never did.
So sure, "Twilight" will probably be considered a classic in the future. But given enough time, all high profile films become classic films eventually, whether through marketing tactics or our own nostalgia. It's really not anything to get worked up about.