It all has to do with the resources available and that sort of thing. Sure, it sucks that things aren't always 100%, but, from having worked at a theme park...
The people who repair the games are basically specialists. It isn't easy to hire specialists seasonally, especially in a market like that where those specialists can be hired to help provide a million other entertainment options.
This, and the last month, is the busy season for the Disney parks. During the busy season, you'll have the most number of games played, and therefore it follows the largest amount of use on those machines. Those specialists will need to pick and choose what machines to repair at any given point in time. Sadly, the pins probably make far less than most of the video games, so the vids will be prioritized, especially because the issues are usually easier to diagnose and change out.
Yes, these are commercial machines and they should hold up better with enough maintenance, but the completely seasonal nature of the crowd patterns makes it nearly impossible to staff to keep everything perfectly functional. I saw how the same company cared for their machines at the park that I worked at, and I give them the benefit of the doubt. It's a MUCH harder crowd pattern to cater to than one who comes into the bar regularly, or to the FEC or whatever.