Where in the real world is it like this? We've traveled all over the eastern half of the US and I never make dinner reservations before leaving home unless we're traveling over a holiday, and yet we've never had problems getting into the restaurants we wanted to try. I don't make dining reservations at home either unless we've got a big group or are going out on a holiday.
Here's a concrete example - we're staying at the Poly in Dec. On our arrival night, there is nothing available at all for dinner at our resort. I have literally never made an arrival-night dining reservation on any non-Disney trip, and I've never been turned away from the hotel restaurant for lack of advanced reservations. Now, I know going in that there's no way I am going to walk up to Ohana or even Kona in December. But an experienced traveler who was a Disney first timer would have no idea that you have to plan months ahead just to grab a bite to eat in the hotel's restaurant on a Wed. night at WDW.