Between two elevators in my building (11 stories) at least one is always out of service for a few days. I attend HOA meetings, and like 8-10% of our ongoing budget is elevator maintenance. Few reasons according to the guy on HOA board:

* the service companies are either Otis or an Otis dealer, so essentially 2-3 companies have an oligopoly on Los Angeles

* all parts must come from Otis (which mattered during COVID supply chains, when you either paid Otis directly for faster service or waited forever for the part to arrive)

* all shafts and mechanisms seem to be custom-built - there's no drop-in replacement service or alternative product (from likes of Mitsubishi or others) we can easily switch to

It's a small industry with few dominant players designed on extracting maximum revenue. Servicing is pretty much mandatory, limited to a few authorized dealers, who know you have limited options.