I may be incorrect but the way I think it works is that . . .
UFTree creates GEDCOMs according to the program that will be receiving it.
UFTree is at the top of a heap of all genealogical programs. UFTree handles more information in more different ways than any other program. As long as UFTree remains 'at the top', the current GEDCOM situation will continue.
What is included in each type of GEDCOM depends upon what the receiving program can use.
A program that can only handle BMDB would be totally unable to pick out and use the BMDB portion of a more advanced GEDCOM. That BMDB limited genealogical program would be confused by a FTM GEDCOM, a ROOTS III GEDCOM, a Family 5.5 GEDCOM, or a Event 1.0 GEDCOM. To export your UFTree project to a BMDB only program requires a particular type of GEDCOM that only contains BMDB information.
A 1.O GEDCOM is for UFTree to UFTree and contains the nearest possible of everything,
a Family Tree Maker GEDCOM contains everything that Family Tree Maker can use, not everything that is in the UFTree database,
a Family 5.5 GEDCOM contains only that data that a genealogy program that accepts GEDCOM version 5.5 can use, not everything that is in the UFTree database,
a GEDCOM version 4.4 contains only that data that a genealogy program that can handle 4.4 can use, not everything that is in the UFTree database,
to send a GEDCOM to a program that can only handle BMDB, then expect the GEDCOM to only contain BMDB, not everything that is in the UFTree database.
GEDCOM is an LDS transfer program, the LDS created it, the LDS control it, the LDS own it, lock stock and barrel. Every so often they issue new versions of GEDCOM that can export more data to ever increasingly complex programs.
Personally, I can wish for someone to produce a more comprehensive utility, one that is altruistically financed by a group that has the money to give this complexutility away. So far, no one other than the LDS has done so. I am grateful that the LDS took their GEDCOM leadership position several years ago. Before GEDCOM, transfers between programs (such as there were programs) was impossible.
I am a pollyanna. I expect good things to happen. I am mostly cheerful. I find the bright side of life. I laugh.
I believe, if UFTree dies, 'twill be a pity. I also believe that another program, either a present programs or a new program will take UFTree's place at the top of the heap. I also expect that that replacement program will grow to at least the quality of the present UFTree. Somewhere in that process, I will be able to 'save' my data by using an advanced GEDCOM to change to the new and improved program, FTM, TFG, or whatever. And, until that happens, my UFTree program, warts and all, will work.