... I do not see how it addresses the security of TMG data for the long term? It seems that even with processes in place to reinstall TMG in the event of a computer failure, the bottom line is that TMG is finished?
For you, how long is long term? In my opinion I do not see TMG as "finished". As I have posted here and on the Refugees list, while development may have ceased and there will be no more bug fixes or new features, the program should still work just fine "as is" for many, many years to come. (As a similar example, my preferred desktop-publishing package ceased development almost 20 years ago and still has more features and works better than many new packages on the market.)
I am desperate to find some other program that will do all that TMG did for me!
You may be "desperate" but my observation of past posts on the Refugees list suggests that currently there is no such other program. Of course, as Terry points out, how close another program will come to "what TMG did" for you depends on which features of TMG you used. Any other program is sure to be "different" than TMG, and while some have recently been modified to directly import "most" of the data from TMG, unless and until they choose to add more TMG-like features you will have to modify the data to adapt to their different way of doing things. They are all likely to have some new nice features TMG did not have, and not have some TMG features you would like them to have.
Because TMG will continue to work I choose to "wait and see" for several years before even considering migrating to another program. And at my age I may never need to use a different genealogy program. Because I am staying with TMG for some time I definitely have the final version, and would recommend obtaining it if you can. Just my opinion.