Several of the courses near me wouldn't be considered walkable either because of long distances between holes (courses not originally designed for walking), or pretty severe elevation changes. A young guy in good shape would be able to do it, but older golfers would be SOL. Also, not walkable from about now through October because it's 100+ degrees every day (110+ a lot of days through most of June, July, August and early September).Not walkable because they don't allow it or because of terrain? I can see some course where they didn't allow walkers before to have it in the future.
There are courses I prefer not to walk just because of the length.