"Magic" of compunding cannot exceed the real growth of actual economy in the long run. Sooner or later something "unexpected" happens - a crash, collapse, a leftist redistribution scheme, a civil war, confiscation or else.
Usury can work only for the few in limited scope. You cannot base the whole society on usury. And money is only a very useful artificial convention which breaks down if treated as actual reality.
The real growth of the actual economy is more dependable than the "promises" of politicians. If we can stop the politicians from destroying the actual economy (I know that's a long shot) then we can increase the real growth.