The FDA deals with the questions in front of them. They have neither the time nor inclination to extend themselves to look ahead. The 'entire purpose' is not their concern. If you ask to give a drug once, and they think that is OK, they'll say OK. That is their response to that question, not the unstated:'Can we give this drug longterm?'
University researchers are obligated to bring revenue into their university, which is how they pay themselves, their staff, their grad students, and for their research program. Going down a road that looks like it could hit a FDA dead end is not a career-sustaining move, unless for some reason they have a strong belief in the premise being tested. They will take on clinical investigations for multiple reasons--a wish to help humankind; a hope to get on the right scientific bandwagon early, or to start their own; and to generate the revenue upon which their research careers depend. I think the other questions you ask (e.g. "are the researchers providing their facilities and equipment for free?") reflect some naiveté that you should correct before you start lecturing people on what companies should or should not be able to do.
<<Maybe I'm just too hard-headed, but I don't see these challenges as any more difficult than for other companies undertaking other studies>>
I have done what I can to provide some information. What you can, or are able to do, with the information, is not my problem.
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