One of the problems with that is that it's like pulling teeth with every single company. If you're in a market like in Silicon Valley where companies know that

One of the problems with that is that it's like pulling teeth with every single company. If you're in a market like in Silicon Valley where companies know that good engineers can be expensive, this may be fine. However, if you're in a market where most companies will offer less than half your current compensation while still thinking they're paying well, and potentially be right about it when compared to many other companies on the market, I am not sure what the best strategy is. You need to filter out the companies that are a no-go from the beginning, and you need to do so early, because the amount of time and energy you can invest in the job search is finite. Giving a (vague, higher-than-current-salary) number that you're looking for seems to be the only way to do so. Of course, this puts you in a terrible position once you do find one of the few companies actually willing to pay comparably.