Derivation of General from "maximum force principle", Review of this method

I just had a look on the chapter "gravitation and relativity" of the
motion mountain on line downloadable book (Author: C. Schiller).
The "derivation" of GR from a statement of a maximum "force" (and
associated maximum power) looks quite surrealist to me. Looks to me as
a mixture of assumptions having nothing to do with GR but combined in
such a way that you get the (already known) right result at the end.
Has anyone reviewed this theory and has any comments about it.

The converse (GR implies some bounds on some physical parameters)
should to be more sensible.
(see GW Gibbons)

.