I think it's the amusement parks themselves that are changing–not the guests. Between advancements in ride technology, an increase in guest attendance (attendance across WDW in 1980 totaled about 13.8 million, which is less than MK alone sees today) and the prioritization of getting as many attractions as possible done in the shortest amount of time (w/ the help of MyMagic and FP+, MagicBands, etc.), the culture of tourism at the parks is fundamentally different. IMO, this is an attitude Disney has actively encouraged in its guests, and definitely not a mark of their increased laziness or poor health or anything else of the sort.
This is a different system but, IMO, not necessarily...a bad one. I would argue that a 45-minute "edutainment" ride ran the risk of boring guests (and children especially) even in the 80s and 90s. A streamlined, modern edutainment ride clocking in at 10 minutes or less can still teach guests something if it chooses a specific enough topic, rather than trying to convey a huge topic on much broader terms within a 15+ minute time-frame. The use of actually relevant IPs (like Inside Out and Big Hero 6, which have been painfully underutilized in Epcot outside of meet-and-greets) could help.