Every post a winner! So I'll try to just add a couple thoughts that came up while reading.
Back a couple years ago, I costed out my marriage, and figured my ex cost me about $150 per. Thing was, it was all front-loaded -- the fun in the first 4 years, the payments followed afterward for about an equal time. Obviously, the average dating guy would have split long before, but the young'un was hostage to the situation and I couldn't.
Canada has some better-than-US rates, because of legality there, so that is an option on the cost curve.
You're almost talking in some places here about Marginal Utility, otherwise known as "diminishing returns" (and wasn't Ibiguana a great wrap-up to this, putting the lie to my concept even before I write it

).
In order to bring the average cost down, you have to, as Prolijo says, "binge". And sometimes that's the whole kick to the trip. So the 7-girls-in-7-days becomes a target for my newbie self as I think about how I would never spend like that at home.
Problem then is, what if you want to kick back for awhile? You can't inventory a $40 ZB session to take home with you. "Must be consumed on premises."
So I would guess the conclusion here might be something like: CR is not a
significant discount overall, and requires frequency while there to get below breakeven. Stateside overhead is less, but it does happen
per session (local travel, work time lost) so the cost of your time is a factor, too.
If you're a once a week/month guy, you really need to do the research and setup where you live.
(And thinking about that marriage calculation again, wasn't that a little like a "binge" trip, too? Only, it started to get paid for when things got spread out a few years later -- to once a week, month, etc. etc.)
Lots of other pluses and minuses mentioned here, but for overall economics, there's probably no easy conclusive comparison. I would say that I now realize I've shifted my budget over from US to CR this entire year, and I'm spending a bit more, and having a lot more fun.
And -- today -- the withdrawal curve begins, for the fourth time...