I think the issue is the average person does not do the research like people on this site do.
They don't go every year, or multiple times a year. They go once or twice.
I'm sure there are many people who show up and have no idea about G+ or any of this stuff.
They are busy with life and may only take one trip to Disney ever, especially after experiencing G+ and all the hoops.
Back when Disney started giving the free
DDP I met an Irish couple who had spent a ridiculous amount of money for their trip. I was staying in the Contemporary on the Club level with a view of the castle. They were in the wings. They paid at least double what I paid (I think it may have been triple - I had an AP Discount BTW). The husband had Stage 4 Cancer and this was a big family trip for them. The
Travel agent took advantage of them and sold them the deluxe dinning plan and basically charged them full price for everything and did nothing. Not unusual in Dublin IMO. They showed up and had no reservations for anything, and found out all they could really get was counter service for the most part. The travel agent told them nothing about booking in advance etc.. I explained much of it too them, but it was too late. I did end up speaking to the general manager, since they would not. In these situations Irish people tend not to complain and actually put up with a lot. One of the reasons Americans have a reputation for complaining, but if you are right then it does not matter. Anyway the GM did sort them out and made sure they had a good trip. This was not Disney's fault, but it still falls on them in the end.
This is obviously a very extreme example, but I'm sure a large percentage of folks just show up and are greatly disappointed.
IMO Disney making it difficult is part of the reason people go to Universal. You really don't have to plan, you just show up and do whatever.