[Update] I am sitting at Nissan to get a bulb replaced, rear drivers side.

[ProfessorGAC]

20. I Get That

But unless it's stuck really badly, it should be easily removed without enough force to break the assembly.
I can see if the car saw nothing but sunlight in the daytime that uV embrittlement would be more likely.
But, I'd think a garage kept car was that old the total uV absorption would not be high enough.
And, there is no other chemical mechanism by which embrittlement would occur.
The most common cause of embrittlement is the slow degradation of the plasticizer, usually a phthalate of some form.
It would take a lot of uV exposure to degrade the additive enough for substantial change in either tensile strength or elasticity.