I come to think that we can't fall massively below 5,000 dollars per BTC - if ever - unless some major whale - of the Mt. Gox trustee's scale - decides to cash out. I base my assumption on the premise that people who bought coins at high prices like over $12-$15k won't be selling at prices below some psychological limit because selling at such prices will be pointless and their only viable option will be to continue holding. So it is not just about demand building up, it is also as much about supply running dry at lower prices. That could potentially lead to less volatility, at least temporarily until a new long-term trend gets established.
As Tryninja mentioned, most people have already dumped their coins at way higher levels by my knowledge so your theory that people will not be dumping at prices below $5k is not really plausible to me, at least. Long term holders most likely wouldn't have bought at $20k in the first place.
What will happen is, at around the $5k mark, demand for bitcoin will start to pick up.
Right now bitcoin is still in free fall. Even though it's going up in price today, it's going to continue the bearishness we saw as soon as this small rally is over.
We could see prices below $5k temporarily, but it'll quickly adjust back up to $4-5k. That's around a 30-40% reduction from right now, which means that $4-5k seems close to being the bottom for me.