How I would keep the price of Bitcoin down, if I was the government you ask? I would periodically seize large chunks of it, and sell those into bull markets, capping the price, demotivating all those with high hopes. Then the 21 mln cap doesn't matter, the hodlers don't matter, and 1 sat never becomes 1 USD. 

Get out your popcorn to watch how the emergent behaviour of Bitcoin will tackle this problem. Systems engineer Nicholas Bowick brilliantly describes emergent behaviour of Bitcoin in this great podcast: https://www.whatbitcoindid.com/podcast/why-bitcoins-design-fixes-money