Back in 2016 we changed the power down time from 2 years to 13 weeks. There were MANY early miners and early high earning authors powering down. It didn't crash the market one bit. In fact as I recall even before the first 13 weeks were up, the market stabilized and started to recover.
The thing is, shortening the power down period does let people power down and sell quickly, but it also removes the overhang of future selling for an extended period. The later can make buying in more attractive.