Many need to let go of the perspective that their personal experience represents all visitors experience. Why should a guest who drives have to pay for this service if they have their own car? Why should a guest who rents a car, have to pay for this service if they have their rental car? If the service is baked into the room rate, everyone is paying for it whether they use it or not. And if they bring their own or rental car they also have to pay to park that vehicle. It is highly likely that if they decided to charge for the service, ridership would drop off dramatically which makes the economics unsupportable going forward.
The same can be said of many services... it's either a 'perk' they offer or consider it a cost of doing business. What about the first aid or mother centers in all the parks? Same thing... not everything is considered to be a self-supporting P&L and that is understood when they decide to get into it. "if they continue it.." is always as you said...
The bottom line is there are many indicators this service was costing Disney more than the benefit they derived from it so they chose to end it.
But the leap in your justification is the idea that the decision must obviously be driven by a drop in the benefit column... simply a 'lack of profitability' or return. But the service was always a cost... so any decision about it being 'in the red' so to speak ALWAYS has to be about if the pain is worth the benefit. But the service no longer being seen as 'worth it' isn't necessarily just because of a reduction in usage. The whole equation and thresholds could have changed.. aka their tolerance.
Disney clearly has the data that is not available to any of us about what percentage of all resort guests actually use the service now as well as the trend over time. It’s quite likely they found overall ridership was declining over time and they saw nothing that would change that trend.
This is a pretty self-concluding argument though. "nothing would change that trend"... you really think Disney concluded that they couldn't convince guests that a free shuttle is worthy vs services that cost a sizable amount of real money?
Most people when facing declining usage (and for DME.. a point that we really have no reference for) they look at what they need to do to make their service more attractive. It's not like the idea that transportation from the airport is somehow a dying market. They know any growth in their own market is always going to have airport usage attached at the hip.
They know the demand is there, and will essentially ALWAYS be there.
The program likely has minimum ridership targets for it to be profitable and they are likely approaching that threshold, which caused them to rethink the program. It cannot be disputed that there are lots more options than there were when the service first launched in 2005 and that likely figures into the ridership numbers as well.
I don't really subscribe to the 'there are many more options' narrative. There isn't any new form of transportation... it's all basically the same as it was before DME. 3rd party shared buses, taxis, hired drivers, and rentals. Just because there are lots more ways to get taxis now and prices have been pushed down.. Fundamentally the picture hasn't really changed. You can say more people take taxi-equivalents due to the price points and perceived convenience... but that is more like a shift in ridership, not a shift in landscape. The people who have been pummeled in this shift are the taxi companies. For consumers, we have more 'high tech taxis that are cheaper than they were 10 years ago'.. but it's not like the basic need and fulfillment has changed.
If anything what has changed in this time period (IMHO) is the demand for people to move around AFTER they've gotten to Disney. UNI is far more attractive than it was in the past.. people like using rideshares for quick trips... the dynamics about maintaining the Disney bubble have changed I think. Not so much the Airport->Disney options.
I think your post assumes Disney has to be doing this purely from a 'ridership drop' and hence the move is sound for that financial decision. I don't think we really have anything to support that sequence except we know Disney is financially motivated generally. They could be simply saying "we're cutting 25% OpEx across the board... what are the candidates..." and maybe they think DME's cost isn't justifiable in the new world order. It doesn't have to be because of usage changing. Possibilities like expectations changing, or competing initiatives are all examples of things that could make a pure cost service like DME drop out of favor in the company.
Think of all the leadership changes that have happened since DME was rolled out. Maybe it simply doesn't have a champion anymore advocating the spend actually justifies the return?
Your point about Disney concluding the return not being there is sound... but we shouldn't assume the way it's measured has stayed the same.