A funny opinion....
I think WDW IS maintaining everything to the BEST OF THEIR ABILITY. The problem? Everything is overloaded beyond human capacity.
Imagine, for a moment, that every week, 3000 people stay in your house. Could you unclog toilets, paint, do repairs, and hire enough maids to keep your home neat & tidy? I could not.
I don't know who does these "capacity" calculations.... WDW IS being maintained: it's just being trampled to death.
Funny opinion indeed, though not at all correct. I've witnessed WDW when it was maintained properly and know what the parks looked like in their prime. There's a lot to be learned from the company's past in regards to theme park upkeep.
First of all, while some issues are guest-caused, just as many are occurring in areas inaccessible to guest contact. Ride effects, scenery and figures that are out of reach to potential vandalism yet remain in poor/nonworking condition for months and sometimes years or decades. Not to mention the toilet-like stench that now pervades the monorail cabins constantly, likely from the air conditioning units not being cleaned properly (a smell which was most certainly never present during my visits in the 90's).
As for the rest, the parks have ALWAYS attracted tens of thousands of guests "trampling it to death" as you put it. They are and always have been immensely popular (their popularity kept Disney afloat during the company's other financial issues of the 70's and 80's). The wear and tear from the crowds really hasn't changed much or at all, what has changed is the company's reactions and the way in which they address (or ignore) such issues cropping up. The crowd and wear levels were always very high (EPCOT, MGM and Animal Kingdom in particular were actually more crowded in the 90's than now), prior to 1994 you NEVER saw close to the epidemic levels of accumulated damage, filth and outright neglect that plague the parks now. I say this without any hesitation (and no distortion or rhetoric involved)- prior to the mid 90's WDW was maintained to such a high standard that it looked practically new. The same was true of Disneyland (and Disneyland Paris for a very short time), which also experienced a similar decline during that general time frame.
Starting around the year 1994, WDW (and Disneyland) began a downward spiral in maintenance due to massive cutbacks to maintenance budgets and the elimination of many night crews positions. Apparently begun by Eisner (and further escalated by Iger), it has been a mistake that the parks have never truly recovered from. Disneyland's issues became so bad that several guests were killed in accidents caused by poorly maintained unsafe attractions (the Big Thunder and Columbia incidents prompted a PR scandal by the fan community that poisoned the park's reputation for some time). DL has since received somewhat of a resurgence in upkeep over the past decade (starting when Eisner appointed Matt Ouimet to oversee a cleanup for its 50th), though it still isn't up to par with the standards the company once held for the parks. Still far above WDW's continued neglected state though (perhaps WDW never got its own resurgence because there was never a PR scandal with maintenance-caused deaths involved, despite some close calls with falling rockwork at Splash Mountain and the Tree of Life).
Prior to 94, refurbishments were more common (which some guests may groan at, though I think it reasonable to say it beats the alternative of rides literally falling apart or with dangerous safety issues). Refurbs not only aren't nearly as common anymore, but it has even become something of a gamble as to whether they'll reopen in better condition than they were before. There have been successful rehabs such as Splash Mountain recently, but there have also been cases where show elements were disabled during rehabs to cut costs. But besides refurbs being more common, there was a far larger army of day and night maintenance crews keeping the parks in good condition (they were also allowed an infinitely larger budget by park ops for general upkeep before the penny pinching began). They'd clean, touch up paint overnight everywhere and kept everything in general looking new and pristine. There were even dedicated crews assigned specifically to JUST lightbulbs, company policy mandated nightly inspection to replace any broken bulbs as well as still working ones that had reached 80% of their lifespan. This meant you'd at most PERHAPS see a rare oddball stray bulb out (which would have been a defective one that had died before its time and would be promptly changed overnight so you didn't see the same one out the next day) as opposed to the vast quantities of broken ones you see nowadays (for one example) on the Grand Floridian's facade (remaining burned out for years without replacement)...
They also kept a large stock of spare parts on property quite nearby for ride elements (such as animatronics). Not to mention employed numerous dedicated crews who were able to work on them (Disney as a whole has now shut down all that was left of their original animatronics department within the past couple of years and now completely outsources to Garner Holt). Broken show scenes occurred far less often than they do now, not only because they were inspected and touched up overnight to prevent such issues, but because they generally had an abundance of spare parts on-hand to fix them in a timely manner. In rare instances that things did break, they were addressed immediately and not left to rot for days on end (let alone months, years or a decade as has become the norm now). Many rides of old were even designed to trigger a ride stop if certain show elements broke and wouldn't start again until the issue was fixed.
Tokyo Disneyland and its second gate Disneysea (despite ALSO often playing host to massive crowds that would put major wear and tear on things) is the one Disney park that is pretty much unanimously agreed to still be practicing the same Disney upkeep standards of old. It is not owned or run by the Disney company, the Oriental Land Company manages it.