The only thing genuinely new about Boost is the name

. AAdvantage has allowed elites missing their status by not earning it during a calendar year to buy back their missed status (a one time option).
AA used to offer a "soft landing" as well, e.g. miss Executive Platinum or Platinum you only would fall back one tier level. Now, with the new enhancements, you cann fall back from EP to White Card in short order.