The problem with BTC vs. fiat price drops is not the investors losing money.
Good trader makes money shorting the asset as well.
The real issue lies with miners.
The level where BTC mining brings profit is around $6,000.
If the price stands below that level for long time, a lot of miners will be OOB.
The exception: Chinese mining companies are still profitable around $1500-$2000.
So problem solved?
No. The problem is blockchain is independent only when none is able to control more than 50% of miners.
And that could happen in China.