I am not sure any bulb really has a reliable lifespan. I bought my house as a new construction 7 years ago. I have individual fixtures that still have the same light bulbs that came with the house (cheap incandescent 60w) I have fixtures on the same circuit where I have changed the CFL 6 or 7 times.
Now of course it could be the individual fixtures, (or even parts of fixtures, my dining room light has one of the original bulbs still and I have replaced all of the other bulbs tons of times), but it seems a lot more likely to me that light bulbs are highly random. I have in my house 3 month incandescent bulbs that last 7 years and 7 year CFL bulbs that last 6 months, it just doesn't lead me to believe there is a problem with my wiring, but rather that light bulb manufacturing and quality control and ratings are highly varied and not at all consistant.
Incidentally I also am typically the one to change bulbs in my grandmother's house (which is 40 years older than my house, and on a different electrical grid/provider about 60 miles away and have wxperienced roughly the same thing there.
My concern isn't that I will pay 60 bucks for a bulb that will last 20 years, but rather will I get the one that will actually only last for a few months, or will I get the one that will last for 70 years. Crazy as it seems, if I am going to pay more than 60 times what I do for a "normal" bulb, there is going to need to be some warrenty, especially since many cheap bulbs vastly outperform their longevity rating, and the energy savings is a very very small portion of my energy usage.