$4600 would prove wrong the theory that Bitcoin cannot go below $5500-ish, which is the guesstimated cost of mining one bitcoin that I've heard lately. So far it seems to be working. Every time it breaks below $6k it gets a huge buy that creates big candle of up to $400+.
This doesn't guarantee anything but it's another resistance to considering given past precedence.
As far as all altcoins going near zero... I am not sure the market as a whole is mature enough to realize how most altcoins are shitcoins and they just should be holding as much BTC as possible on their portfolios. So when the next hype for crypto comes, I still expect another altcoin bubble.
And people said Bitcoin never went below its previous ATH until it did in 2015.
The markets don't care what anyone pays to mine a coin. That's the miner's problem and no one else's and I'll guess we might be shocked at how cheap it is for certain groups. Perhaps miners are in there batting away at the price but that seems like a rapid route to total ruin.
I've stopped giving a shit about the near term Bitcoin price. It'll be fine in the end. Is the $4000s possible? I don't see why not.