> The free market is supposed to weed out the chaff.
The free market doesn't care about stability, but we as the people that deal with the market, should. An unconstrained free market will swing wildly, which is one of the ways it will identify the chaff to cull, or depending on how low the swing is, the not-quite-as-good wheat to cull. The US has long recognized the benefits of a steady economy though, so while there isn't as aggressive culling, allowing some mediocre companies to survive, the environment itself is more amenable to sustaining a population of people which is the whole point of the economy.