This topic is always a little loaded, because while it is definitely very noticeable and getting worse by the year, there's also always going to be a subset of entitled types that react like: "That CM didn't reply to my question while grinning ear to ear and call me a Mouseketeer (while being in hour 9 of their 12 hour shift of getting yelled at over and over trying to explain Lightning Lane)... where has the quality gone??"
As someone who was a CM from the mid-00's to mid '10's and is still actively part of the Orlando theme park worker community, I absolutely have noticed the level of enthusiasm from CMs decline significantly since my time there. But I still feel that the average, the level of service from Disney CMs is still better than most places, especially considering all that they have to deal with.
There are a LOT of factors here, and while maybe I'm not touching on anything that hasn't already been said in the thread, this is my perception based on my experience.
1. Staffing. WDW is just too big and the Orlando job market has spread exponentially over the last two decades, and is about to explode even more. It has reached a point where WDW literally can NOT function without the College Program and International Program. What was once a mutually beneficial supplement to the company is now the bread and butter of their frontline workforce. In the past, College Program participants made up a much smaller percentage of overall frontline staffing at WDW. Today, it's gotta be something like 30-50%. If you are at a park at closing time, chances are about 80% of the frontline workers you see are College Program participants.
So they now shuffle in and out more CMs than ever before every few months. This means that the quality of who they accept into the program is lower, the training they get is more expedited, and that at any given time a significant portion of the workforce is new (and honestly there's so much to know about WDW that anyone working there for under a year might as well be "new").
2. WDW has one of the most toxic work environments possible and has built up a corporate culture that rewards intense, cutthroat backstabbing and favoritism and not hard work/passion/enthusiasm. This lowers work ethic all around. Why go "above and beyond" when you watch, over and over again, the apathetic CMs who are merely good at "playing the game" get promoted instead? The full time and part time CMs end up burnt out, and this attitude also carries over to the CP's.
3. Disney has made a visit to WDW so ridiculously expensive AND convoluted. The guests are frustrated. The cast, even if they want to "make magic", have a harder time doing it now when the guests are so frustrated and confused and need constant instruction.
4. The attitude of the general public, basic empathy, and level of entitlement has absolutely plummeted ever since Covid. We've all seen it. Disney leadership IS at least aware of this and has backed off on punishing CM's over frivolous guest complaints because of how awful people have become. Combine this with #3 and, yeah, you get a work environment that's very hard to stay positive in. Note: This is NOT me making a "get off my lawn!" rant! Everyone I know who has worked in the parks since pre-Covid has noticed this decline.
5. Gen Z, which makes up most of the WDW frontline workforce now, in particular has grown up watching their elders get continually crushed by corporate greed and BS and has largely decided they are putting up with none of that. As an elder millennial, I agree with the sentiment, however, I feel that it lends to many of them believing that being asked to try at all at their job = "abuse!"
6. Older generations of Americans became accustomed to associating overly fake-friendly service with loads of corporate speak as "good service", while the younger generations are increasingly viewing that as off-putting, cringey, and at times, condescending. So what one person deems as "apathetic", another might prefer that style of response from an employee.