If you believe the only way to take a profitable short that has a component of probability to it, is to wait for a support and/or trend line to broken, that's just amazing to hear. I mean I guess it depends on what you quantify as support, if you're speaking of actually losing structure than I could more agree with your statement (although still that is not the only way to gain an edge).
If you simply mean I need to wait for the markets to drop and break weekly support levels, before gaining a probability edge on a short or taking profits, yeah we're too far apart to even have a conversation or debate on that.
Just think about how you're viewing the market for a minute. You're viewing it through a lens of being long at a lower position and from a longer term perspective. So, you're all calm just waiting to see if major support holds. Excellent, nice job no issues with that.
Here's where I have the issue. You don't look at the market from the perspective of other investors / traders. Not everyone has the means, intelligence and/or discipline to be patient or make intelligent decisions when it comes to the market, I think we can agree on that right?
The point is you have buyers coming in at either all time highs and/or current relative highs on just about every product and every chart tradable at some point in time. Sometimes this setups up a long trap, which can be identifiable and tradable. where they will squeeze out the weak buyers. This opens up a temporary imbalance where you can trade short and trade against them with a probability. No of course it isn't 100%, nor is the setup always there. But there's tons of players in the market from short term, mid term and long term. There's probabilities besides just averaging down and waiting for weekly, monthly or whatever support to break.