Currently BTC prices have been hovering at 6000, and if the BTC prices fell to $5000, $4000 should be not far off, the market is confirmed in the bear market, want to rise to $20000, you may need a couple of years.
Sad to say but it won't even touch $4,000. $20,000 maybe to far but I think it is reachable once the market recover. Demand for Bitcoin is more influential than selling it at a very low price.