Calendar types in watches

First off, not all Calendar complications are made the same. The standard Patek Phillipe Annual Calendar needs only one correction per year – from February 28 or 29 to March 1. The 'plain calendar' complication needs adjusting five times a year for months of less than 31 days, but the far more popular perpetual calendar requires no adjustment whatsoever.

Secondly, your argument is fairly analogous to having to tune a Violin when perfectly good Violin virtual instruments and samples exist, indistinguishable for the use-case in question. By framing the question like that you're kind of missing the point about Horology and owning mechanical trinkets for the sake of marvelling at their construction and innovation.

While the rest of what you said is true, perpetual calendars require setting for the year 2100, still a while to go though!

There's still a big difference in the sound of an actual violin and a digital recreation. But both a mechanical and digital watch will display the same information.

The article points out some mechanisms that account for that.

However, at that time scale, I have to wonder whether the mechanism can, or should, run for over a century without stopping, which would seem to imply running without being cleaned or serviced beyond a certain point.