In addition to the matter of speed bumps – sabbaticals spaced periodically to keep the valuation of momentum from growing too large and overwhelming the political/economic system – there is also the matter, during the intervening six years, of establishing banks of surplus (chelev & dvash (?)).
These banks are the other side of the coin of the speed breaks. The accumulation of the surplus for six years is the result of, and complementary with, the imposition of speed breaks in the seventh year. Both are elements of the laws of sheviit and shemitta, though the laws that focus on the shnat shemitta, the sabbatical year, tend to draw far more attention than the laws that would focus on the shanot chozeq, the productive years.
Perhaps that is because the chozeq years were the responsibility of the mundane leadership while the sheviit and shemitta years were the responsibility of the ministries of the divine authority.