Even productive old people can't bear children. Even non-productive young people can bear children. If you "cull" young people (by war) you make the problem w

Even productive old people can't bear children. Even non-productive young people can bear children. If you "cull" young people (by war) you make the problem worse by having even smaller working-age population later. Of course you can lose and have incoming invading horde which may solve the problem, FSVO "solve".