My regular group has recently spent the better part of an entire dinner debating this topic.
We like to think that we discussed most relevant parts of the argument. We looked at it from private club and public access perspectives.
Our conclusions to speed up play came down to two fundamental points:
1. Reduce one's "pre-shot routine" to under 25 seconds
2. While not quite being "ready golf", players must be ready to hit when it is their turn: know yardage, select club, think about shot, etc.
My pre-shot routine is 18 seconds. (From the moment you put tee in ground to when you hit the ball, as an example.) Tour average is 37 seconds. Bernard Langer is 45+. If the average amateur can trim 15 seconds from a pre-shot routine (40 seconds to 25 seconds, inclusing putting), that means:
15 seconds x 85 shots x 4 players / 60 seconds = 85 minutes. This turns a 4:18 round into 3:00 round which is my group's average. Now, I'm a realist, so let's just cut that number in half and say it saves just 40 minutes...still, not bad.
Then add being more prepared and that number can drop.
Most recreational golf I have seen (at resorts and munis) is painful as players watch each other instead of paying attention to their own preparedness. Easily adds 15 seconds per shot per player. The again, let's cut that in half.
You combine these two things, you can get a 4-ball around 18 holes in 3:00 and NO ONE will feel that they rushed or hurried. Sure, when you have matches of highly skilled players, you may see more time taken. But. I am talking about your Saturday morning $5 Nassau with your buddies.
It works.