Matt,
I don't disagree with what you've said, and years ago sent a note to the USGA regarding exactly what you've stated.
A solution that a club in New Jersey came up with was simple and worked until they stopped enforcing it. I understand that they will be reinstating enforcement next year.
No mulligans are permited on the first tee, otherwise the entire foursome gets a slow play letter.
As soon as the last member of the foursome tees off, the clock starts running, when the last member of the foursome putts out on # 18, the clock stops.
If play is over 4 hours, or if the group is more than 10 minutes behind the previous group, the entire foursome gets a slow play letter.
Two slow play letters result in not being able to tee off until after 12 noon for two consecutive fridays, saturdays and sundays.
An additional letter results in a month of delayed tee offs,
A fourth letter results in delayed tee offs for the season.
No personalities are involved, no confrontations, it's simply,
the differential between time out and time in, with the 10 minute provision. Groups that fall behind somehow find the way to catch up, since all members of the foursome are responsible for fast play, and suffer the consequences of slow play.
I'm shocked more clubs haven't implemented the system.