Reliable is just an ambiguous word in this context because it only means certain aspects are reliable. Just because reliable is usually equated with good doesn't mean it actually means good in all contexts.
For instance a direct drive mechanism (gears instead of belts) with few moving parts and sloppy tolerances on those few parts will be will be highly reliable, in that it will run every time and run forever. "sloppy tolerances" is usually a bad thing but it also means it never gets stuck. This is in general not just a tape drive. But it's garbage for this application because a tape drive isn't a rock saw.
To make any kind of analog signal handler, the mechanical parts need super close tolerances, which means they more easily stick from dust, oxidation, or dried out sticky lubes, and has fragile elements like rubber belts and rollers that all age poorly and even suffer from normal use like getting glazed, and even suffer from not getting used, like rollers forming dents where contacting parts rest for too long, belts taking on the shape of a pully, sticking to the pully, etc. Basically even though the better mechanisn is much more expensive and does the most important job better, one thing it's not is more reliable in the way that a hammer is reliable. It's delicate and needs lots of care and maintenence, and that is not the result of poor engineering or manufacturing or quality.