Overall though, I think the results in various areas matter moreso than time...as time is a matter of luck more than anything. There's nothing to say the guy behind Incursion couldn't get struck by a "mood" ala in Dwarf Fortress and bang out the rest of the game relatively bug free by the end of this year. It shouldn't even need to be considered how long something has been at it to get listing amongst the big dogs but rather what nifty things the game does period.
That's the critical thing right there, once listed in the same breath you attract more/new players, who can then enjoy and contribute, which then naturally, yet artificially, ramps up the game quality, which attracts more, and so on. Essentially, the more people freak out and make a big deal about the latest well deserved version or patch or whatever for as many Roguelikes as possible----the better. There's no harm at all in having a very long list of greats at their various strengths for newcomers, active players, and returning old timers---in fact that should be the goal of such to be able to objectively say "Yep, this works and does cool stuff...into the list!" as often as possible, sooner the better for the sake of progress and more people getting to enjoy a more abundant variety of games. Liveliness is the key to the future in Roguelikes same as all others.
/gets off his madman soapbox...for now....
