I got a picture. Thanks. So there is no such thing as doing thing other way if the best way is not obtainable.
Not quite. Some programs might for example, be optimised to use one thing, but be able to use an alternative and will check for both, use the best if possible, but otherwise use the other one.
As for the FORTRAN thing, I'm not sure - very few programs would want to use this. I've been wondering about this myself, but I don't think it's anything to worry about