Not automatically. The two layouts fail in different places, and the difference between a good example and a bad one is far larger than the difference between the types.
A saildrive adds a rubber diaphragm sealing the leg to the hull, an aluminium underwater housing, and a corrosion-control system of anodes and approved coatings that must be maintained exactly as the maker specifies. The diaphragm is safety-critical and time-limited — one maker's interval must never be applied to another maker's drive.
A shaft drive adds engine-to-shaft alignment, a shaft seal, a cutless bearing and a stern tube. Those wear, and misalignment quietly destroys mounts, seals and couplings over time.
Judge the individual installation: documented maintenance, the state of the anodes and coatings, the age and history of the diaphragm or the seal and bearing, and whether the last owner had the work done properly. Condition and records decide reliability, not the stereotype attached to the type.