However, even tough I think it will probably never happen but if price goes under 3000 one day and reaches to 2900 or even 2700 levels we will see the support lines change drastically, instead of 3000 levels of good support we will have 2000+ of good support. Support lines at 1900 are useless right now so there is no need for them toe exist but if the price goes down than the support would go down as well and create a good support line there.
I do not think you really understand how these support lines come to existence, you talk about 2000+ being a support, what is a good reason for anyone to buy bitcoin at 2500$ for example? support lines are price areas where there is a strong physiological history of people buying at the area.
if the current support area is to be broken, i personally will short bitcoin, never going to long it until i see 1900$ or 3000$ again, it's only logical that you keep your SL closer to where price is likely to oppose.
if bitcoin drops below 2800$, the probability of it going to 1900$ is much higher than going back up to 3100$, from a trading stand point, it only makes sense that you short btc at 2800 with SL at 3200$ and TP at 1900$ , as oppose of buying at nobody's land below a major resistance.
look at the chart, when btc fell below 6k, where did it stop ? where are the new support lines you talking about? it only stopped right at a previous support, and if it falls from here, chances are it's only going to stop at the next existing support, it's text book really just watch the chart, history repeats itself most of the time, while anything thing can happen and price can retrace at any point and time, i still suggest that you don't try to beat the odds because they will beat you harder.