I see the trains EVERY DAY. I know what there condition is, and I know more about their condition than a guest who visits a few times a year. The guests are the primary reason the trains stay in the condition they are in for as long as they do. Disney is being gracious by making sure the guests have transportation to and from the Magic Kingdom and Epcot, and when the trains are down the guests get angry.
Those trains go though hell every single day because the Magic Kingdom is open all the time for the guests. Guests leave trash, stain the carpet with various fluids, scuff up the moldings, tear up the seats, etc. The management does not do that, the cast members do not do that, only the guests. If you want the trains in the condition they were when new, that will never happen unless the trains go out of service for an extended period of time, and once again if you following the pattern, guests will complain constantly in the parks and on this very website. Disney can't win.
So when Disney IS investing money into the trains, in more ways that you know, instead of complaining that the carpeting isn't perfectly straight, enjoy what you have because I guarantee you that the carpets won't look new once summer comes.