"The hand-blown, carbon-filament common light bulb was manufactured in
Shelby, Ohio, by the Shelby Electric Company in the late 1890s; many just like it still exist and can be found functioning."
Two things to be gleaned from that:
a) It's not the only one, then, just (presumably) the only one with an unbroken, proven provenance*, and
b) Maybe the fact that it's hand-blown and (again presumably) hand-assembled will have given it and its kin quite a wide variation in component quality. Hand-blown glass will by nature have relatively inconsistent thickness compared with others in the same batch, as opposed to mechanically mass-produced glass which will be absolute uniform. Equally, the filaments may also have been hand-assembled, and as a result some may also be more robust than others. These will be vacuum bulbs, so the stronger and thicker the individual elements the longer-lasting the bulb will be, provided it's not damaged. As this one is in a fire-station, it's a fair bet that it's on a relatively high-ceiling, and therefore less susceptible to being knocked or struck by accident.
None of which takes away from the fact that it, and others, have lasted this long.
As for planned obsolescence, I've never been able to really make up my mind about it. Generally, I think manufacturers have for a long time (especially post-WWII) concentrated on making consumer goods cheap enough that people will just replace them when they go, as opposed to making things very expensive but equally more long-lasting (I'm old enough to remember when everyone had to rent their colour TVs, in the UK at least, as they were so expensive: now, if one develops a fault, you'll just buy another as they've become that relatively cheap.) Once they'd worked out how to make bulbs for - I assume - next to nothing on a huge scale, which in turn implies materials as cheap as they can go, then they're bound to be less durable. So, I think for a long time it was probably more about acceptably eventual obsolescence than deliberately by design, although of course the tide has turned now, and renewables and durability are becoming far more important. Maybe we'll see more centennial appliances in a hundred years.
*is that tautologous?