The 10,000 hour figure comes from Ericsson's research, studying "the cognitive structure of expert performance in medicine, music, chess, sports, and many other skills, investigating how expert performers acquire their superior performance through extended deliberate practice, high concentration practice beyond one's comfort zone." I like that emphasis on deliberate.
I am reminded of one of my first guitar teachers, who reminded me that practice makes permanent (along with an admonishment to practice well and carefully), and coach Vince Lombardi's similar quote, "practice does not make perfect, only perfect practice makes perfect."
Sitting in perfect physical form on a professional zafu for 8 hours a day may not do much if you're off daydreaming the whole time. In fact, I sometimes wonder if such people aren't sometimes ending up worse off, i.e. by practicing and perfecting their daydreaming skills. Instead of practicing being in the here and now, gently investigating, exploring and relaxing in presence awareness, they end up spending too much time practicing the default network, the wandering mind. But I may be a bit pessimistic here.
10,000 hours is a nice rule of thumb, but certainly people who practice regularly, intelligently and deliberately, making use of resources such as the pragmatic dharma community and personal coaching as needed, can often attain stream entry (1st path, the first level of enlightenment in Theravada Buddhism, the tipping point) in 6-18 months, perhaps 500 hours on the cushion. In my and many other people's experience, regular daily practice is more important than long retreats (in fact I've met post 4th path yogis that have never been on a retreat), but some long sits can be useful every now and then. And ...
... it does appear, anecdotally, as if some exposure to some psychedelics may be useful in the awakening process. The studies being conducted now @ Johns Hopkins on psilocybin +/- meditation ("the latest psychedelic research ...new meditation +/- psilocybin studies") may yield some insights.