I feel like you can't discuss WDW maintenance if you haven't even been in the parks in the post-Pressler years. That much lost ground takes more than one or two fiscal cycles to clean up! I've been visiting WDW at least twice a year for about half the time the OP hasn't and I believe they receive rigorous maintenance. On this board, Disney Parks cannot win. If big attractions go down for overhauls, they're mismanaging the parks. If a clock stops ticking, it ruins a park day. Sunscreen delaminates paint from plastic and plastic from plastic (this is true, by the way - SPF 50 is like acid on many plastics) and people post pictures and berate City Hall. Contrast this with the fact that entire swaths of the parks are covered in themed scrims for regular painting and cleaning. I see maintenance during every visit. I believe standards are very, very high. High watermark, industry-leading levels.
What ruins it all too often is the complaining around here.