It is not possible to keep the price down with Crypto (as it is not possible to print) but it is possible to keep a price floor by buying up reserves. Trade has downward pressure.
I gotta disagree. There was no price floor for Tabasco the bull no matter how much people hoarded them - because they were useless. Velocity and usefulness correlate strongly.
If a person/group decides to set buy orders for Bitcoin at $1 and they have 21 million in reserves, then they have put a effective price floor on BTC, it is possible to do.
This is in contrast to keeping 1 BTC under 10 usd, that is impossible, since anyone with 210 million (a lot less, but extreme example) would be able to pump the price up by buying it.