I really appreciate the effort you put into your answer, links and all. The most interesting to me was the academic-philosopher-becomes-zen-student essay because it attempted to assimilate the practice in somewhat external terms.

I still sort of feel like I'm hunting for a really practical "cashing out" of the benefits I guess. I presume that there are benefits, because social practices usually have some basis for persisting and truly selfish memes appear to me to be relatively rare, so I'm willing to hang out waiting for the value to shine through :-)

Nonetheless, it seems like it would be irresponsible to not at least consider the idea that there actually isn't any net value to expert level meditation practices, but only a small amount of value that's outweighed by the costs, with an overvaluation that grows from cognitive dissonance about sunk costs.

We start meditating with some such low motive; because zen is cool, to feel special, to fight akrasia, or because meditation is hip nowadays. I started mostly because I was curious and to feel special, and that is probably still a partial reason to continue. And that is all well and good. Several sources say that if beginners knew what it was about, they wouldn't start at all.

I think this works as a description of many practices other than just meditation - juggling for example! Still, this is the sort of thing I might expect to hear if cognitive dissonance was an important factor for understanding the situation.

Of the benefits there, "fighting akrasia" seems like something that would deliver clear value, if it was an actual benefit. Less akrasia would lead to more effective execution on actually worthwhile plans and that would, by definition, lead to better outcomes. However, that's not the kind of benefit I usually see touted by skilled practitioners of meditation. Instead I tend to see talk of "feelings of enlightenment", "compassion", and maybe some interesting "spirit quests".

So if I'm (1) feeling enlightened enough, (2) already feel compassion for poor people and would actually prefer to feel less while doing more to help people, (3) would rather take drugs or sleep in and have a lucid dream for my spirit quests, (4) directly reject the accuracy of the first noble truth, and so on and so forth with reasons to ignore "internal feelings for their own sake"... in that case what are the "external payoffs" I should look for with meditation? Do I get an IQ boost that's likely to generalize into greater efficacy and higher wages? Do I get to control my personal demeanor to improve my relationships and get better outcomes when dealing with people? Am I more mindful and therefore less likely to get into car accidents (or win sword fights)?

While appreciating that you've helped me understand more about the practice, I guess I still feel like I'm looking for starting points to build an ROI calculation with estimates for costs, risks, benefits, and timeline that can be summed to see if the "percentage gain over time" beats the prime lending rate :-)