Talk about dedication to one's gear.
I probably would have followed Neon's thought and overcharged the new buyers for the actual cost of the speakers and have that included in the house sale.
That way you could have replaced them and still pocketed a bit extra, assuming these people wanted the speakers that badly.

Either way it sounds like you're back on a more positive and happier path.

"Those who preach the myths of audio are ignorant of truth."