There's a harpsichord in my family. The traditional harpsichord had a wooden frame, thus the materials just weren't stable.
An American maker, John Challis, developed a harpsichord using modern materials, that stays in tune for much longer.
They didn't take as long to tune, as mentioned above, because the historic temperaments were easier if you knew what you were doing, and there were no unisons (multiple strings per note) to get into agreement. Before the age of the modern piano, keyboard players had to tune their own instruments, so it was just part of learning to play.
The Challis harpsichords are fascinating, but I think also a bit of an acquired taste. The aluminum parts sound odd to me, but I assume they basically never lose their tuning.
An American maker, John Challis, developed a harpsichord using modern materials, that stays in tune for much longer.
They didn't take as long to tune, as mentioned above, because the historic temperaments were easier if you knew what you were doing, and there were no unisons (multiple strings per note) to get into agreement. Before the age of the modern piano, keyboard players had to tune their own instruments, so it was just part of learning to play.