I have not read this whole thread either..... but isn't it all about what brings you personal satisfaction/fulfillment when everything is said and done?
Comparing the process of getting a PhD to getting an MD is kinda apples and oranges, if you're talking about compensation/cost. A more accurate comparison is PhD programs vs residency programs. Both treat you as cheap labor, for starters.
A PhD program might be (arguably) easier to get into, but not so easy to get out of (w/ degree in hand). And then what?
I for one can no longer stand research. I would hate to spend my time (continuing to) pursuing esoterica. I will no longer tend to cells/animals/samples/preps/gels/slides/ecoli at ungodly hours and on weekends and holidays, though would be more than ok spending the same time on people in a clinical setting. Research to me seems like a gigaton of effort that may or may not yield a femtogram of theraputic value... and that may not pass all the stages of FDA approval... and even if it did, it may only be accesable to the few that can afford it. Or bounce back and get taken off the market. I need a bit more "closure", or at least the promise of one... sooner rather than indefinitely/in a few decades, or more likely, never.
I already get shat on by my boss (who incidentally is NOT a PhD but is an MD- and it shows, in a bad way... so clueless about the daily realities of research, so filled w/ typical MD pomposity). I'd rather get shat on in clinical medicine (or on my way to it) ..... And he is an example of how if one has an MD, they can do research AND clinical practice. But a PhD, as far as I know, is pretty much limited to research (psych excluded). There are plenty of MD's and DVM's that leave the clinic for the lab.
As an aisde, I've seen more than a handful of PhD's (and abd's- all but dissertation/defense) parlay their degrees into some sort of biotech-du-jour company. And how many of those make it? or even get sucessfully bought out by someone bigger (a common "exit" strategy in all of business). Speaking from experience, I couldn't deal with pimping myself to investors, bankers, lawyers, patents, PR/media types, living and dying by grants, running through regulatory hoops, etc.... again, that's just me.
Another option after a PhD is academia. I dare say that landing a quality, tenure track job in whatever field your PhD is in is MUCH harder than finding a job/setting up shop as an MD (extreme specialties excluded)... this is true even if you are an idiot of a PhD. The trend is to hire fewer and fewer tenure-track positions and use more "temporary instructors"- many of whom are desparate PhD's. I have seen this agonizing process in so many science PhD's. Perhaps PhD positions are more sensitive to trends in the economy than MD's?? And those PhD's that land jobs still have to live and die by grants.
Personally, I have come to be extremely disappointed with the PROCESS of research, both in academia and in industry, (start-ups and corporate). There are few things that I can think of that are as disappointing. Not that the "process" of medicine is w/o severe faults either. (One thing I do I know w/o a doubt is that the jerks I've met in science have prepped me well for the ones in medicine... and on a percentage basis, medicine has many more jerks... hopefully I'll be proven wrong, but I doubt it).
Every job/field has their own unique set of BS to put up with. To me the pain and BS involved with research/PhD is not worth my efforts, whereas it's worth it for clinical medicine/MD. I could be wrong or I could change my mind. Unlikely, but possible. And if so, I'll just go back into research. or farming. or chef school. or whatever.
just one person's perspective/experience.