Strong support lines are always harder to crack, not impossible like you said, but harder. Which means there will be plenty of people who will put buy orders at around 30k and then sell orders at 29.5k, that way you would be losing only a little if you are wrong, and if you are right then you would be buying at the bottom and it will go up. That's the type of thing that you could make money if you do it constantly.
Doesn't mean that you need to do it once a day, but you could always see it bottoming out at a strong support level and if you know what you are doing then you will end up with a profit. It will certainly cause a bit of trouble to be constantly online, so you could also use a trading bot to do the same thing.
They are harder to crack only during the periods when it is not really that bad. When the market is not really that big, you end up with support lines or even resistance lines not getting broke that frequently. However, when you end up with something that is a bit more serious, like a big crash, or a big hype, you end up with something that is a bit more understandable and it's easier to crack.
What I mean is, maybe 30k will not get broken down under and the price will not be there, but if it were, it wouldn't be just slow by slow, we won't see 5% per day drops few times a week for months before it goes under that price. We are going to see a huge crash that happens like in a day and go to near 30k levels, like maybe 32 or 33, and then we will see under 30k after a few days. If it ever happens, it will be like that.