If biking continues to grow in popularity and gets used more and more, that should help keep the maitnance of them in the fore-front.
Except we've seen how well the city and state take care of road markings for cars, and cars are pretty popular. Adding legitimate bike lanes makes road markings that much more important and I don't know if I trust the city and state (depending on jurisdiction) to maintain them to a necessary standard.
Lurker: While I was mainly using segregated bike lanes as an example of infrastructure that the city/state could build and neglect (for at least some time). I think you and I are both in agreement that the region's track record on keeping road markings in good condition is lacking at best.
Furthermore, I know that segregated bike lanes wouldn't work in much of Boston. You would need to sacrifice on-street parking in most cases. In the Financial District, where on-street parking could be done away with, the streets are narrow enough that speed and segregation aren't as important. In places, like along the Back Bay stretches of Comm. Ave. and Beacon St. where cars tend to fly because they are wide one-way (or divided two-way) streets, on street parking is essential.
In addition, most of the places that fit the bill for segregated bike lines (at least in the two examples I can think of below) are hardly places that would ever get the moniker "livable".
http://vic.gedris.org/node/295
boulevard de Maisonneuve, Montr?al. A one-way that passes through downtown Montr?al. Cuts through a canyon of office towers, hotels and shopping centres. In many ways, de Maisonneuve is the 'alley' for more the more popular streets of Sherbrooke and Ste-Catherine.
http://media.photobucket.com/image/University Avenue Toronto/thecharioteer/UniversityAve.jpg
University Ave., Toronto. A pilot project that was cancelled before it got off the ground was to see the interior lanes of each direction closed off for bike lanes that would be segregated by flexible bollards. In the event that the pilot was successful, the plan was to put more permanent infrastructure in place. The plan was cancelled due to a lack of money, though I'm sure the cries of the suburbanites who drive downtown didn't help. Now, with a new, pro-car mayor, this idea will not be resurrected anytime soon. University is nothing but hospitals and office buildings. A few condo developments are taking place but nothing that will be able to change the overall desolate feeling of this street.
Again, I'm not necessarily advocating this for Boston (though, I do think there are some contexts where it could work, like the new Western Ave. stretch, especially given that double line. Flexible bollards or a small concrete divider could work well there), just more showing how, in certain contexts, they can be useful for keeping cyclists safe on faster streets. I wouldn't recommend them for slower, more mixed-use/residential areas.