Hi wattage, low wattage, specialty, halogen, many types of filament bulbs are still available and being manufactured.
But if you want to keep something warm, look for "heat tape" in the plumbing section. Or for infrared heat lamps (typically reflector spot type) in the store. The heat tape is designed to keep pipes from freezing up and there's no filament to burn out.
Incandescent bulbs are (were) cheap and convenient, but there are better ways to generate heat.
Question on the Heat Tape:
How much heat can they take without burning up or becoming ruined.
I'm asking because I'm curious if heat tape can be wrapped around engine parts as well as through hulls.