Because its a RESORT - not just a theme park. Just like in the past you'd spend time doing water sking, canoeing, swimming, visiting the horses, etc. All valid and great parts of a vacation that have nothing to do with a Disney character or park.
Disney's dining experiences used to be unique and they were just as 'new' and 'exciting' for guests as it would be to travel to a far-away land.
The dining experiences used to be about the land or location... and give you an immersive experience that tried to be equivalent to the real deal. Be that classic hollywood, the south pacific, Japan, or even a time warp to the 50s. As much as POTC was about taking you back to see/experience a pirate encounter... Disney Dining was about top notch food and environments.
Enjoying those experiences was just as significant as it is to see a land in World Showcase, or experience some fantasy world, or go back into some childhood fairytale.
Alas much of this has taken a backseat to DDP and the rush of society today - seriously eroding the atmosphere, the menus, and the update and expansion of such experiences.
Now, with all the meat stripped out.. we are left with just the core skeleton of expensive meals and limited selections. The lure is severely limited compared to the past.