Garland, I believe he meant that weekday play makes up half the revenue. I doubt it as those rounds are often discounted to that of weekend play and weekday players don't spend as much on other things. But, many weekday players are retired and older. Don't forget about things like arthritus (trust me, I don't). As much as I dispise them, carts are a part of the business model. If courses didn't generate revenue from them, they would need to get it from somewhere else - like raising greens fees, practice balls, food & bev prices.
Since you like to walk, what skin is it off your nose if someone rides? You should be thanking them, they are subsidizing your golf. As for caddies, I don't know if many clubs make any money on them and would suspect that it may cost money (caddie master) on the net.
It would be interesting to see a list of walking only courses. I know The Dunes Club is.