Fad or Classic? Is nearly 3 decades enough to know?

Before the era of the Masses Media of the Internet, YouTube and Boardgame Geek there was an era of Mass Media such as mass-circulation magazines, daily newspapers and three TV networks.
Every so often in that earlier, simpler time, a board game might bubble up into the general consciousness and get attention in the form of articles, television segments and book sales and become a fad. Games such as Mastermind and Backgammon would be hot for a while.
In the early 1980s a couple of rather similar games first published in 1979 popped into prominence. Each was a variation on an ancient classic, the invention of smart young guys and picked up by major game publishers. Each had regular and travel editions that were widely available in non-game outlets and even had a thin strategy book or two published.
Nearly thirty years later, though, their paths have diverged somewhat. While neither is wildly popular any more, Pente seems to have held up considerably better than its contemporary Kensington.
Kensington is essentially a more elaborate version of the very ancient game Nine Men's Morris, which is at least 4,000 or more years old. It's played on a considerably larger and more intricately shaped board than the older game and eliminates the older game's capturing rules, repositioning pieces instead. The winner is the first player to occupy all six points of one hexagon.
Pente is a slight variation of an almost equally ancient game, ninuki-renju, played on the same board as Go, another game that dates back many centuries. In this case the designer added a capture rule to the five-in-a-row configuration game.
Even though Kensington was a German "Game of the Year" nominee in 1982 and seems like it should have fared at least as well as Pente as a simple and quick-playing abstract strategy game, in fact it's lustre has faded considerably since.
Even though 404 members of BoardGame Geek list owning a copy of Kensington (as of Feb. 23, 2008), between them they only report a total of 54 plays, an average of .133 plays per copy. In comparison, 1,210 BGG members have a copy of Pente and they've reportedly played them 1,638 times, an average of 1.35 times each.
My own take on the two games is that Pente is more attractive-looking in play, is more tense almost from the start and feels like a more elegant design. Kensington shares with it's older ancestor a two-phase style of game play with an initial placement phase and then, one all pieces arrive, a phase of moving units. Both phases are rather slow-moving and, frankly, often boring. While they can be very strategic can reward long-term planning, they can be pretty frustrating between evenly matched opponents. Removing Morris's capture rule does not seem like an improvement for Kensington, making the struggle even more drawn-out.
Pente games, in contrast, have a built-in time limit and the best end games see both players teetering on the edge of disaster. But the game will soon end when it reaches that point.
So I do think that the verdict is in on both games, Kensington, it turns out, was indeed just a fad. Pente, while not a blockbuster, will remain a niche classic for years to come.