Most people ignore these contacts, so it does kinda work to match needy recruiters with underemployed IT pros. But when you're already at FAANG making 400k a year, it can take a recruiter phone call, two tech screens, and an onsite before compensation comes up, and you're now invested like 10 hours into a negotiation where your BATNA exceeds whatever budget they have written down. I've had one recruiter get a bit angry even over it, as if my number was unrealistic (I assume they were unprepared to make a competitive offer).
Since there are so many of these lowball recruiters, some people resort to screening them out up front with a salary negotiation.
If you don't set some kind of expectations with a recruiter then you might end up in processes where the 'negotiation' happens at the back-end, when you've been through the hoops, and the company has no chance in meeting what you're looking for.
This can waste a large amount of your time. Which is probably valuable if this is a situation you're concerned about :-)
It's not so much that as a negotiation technique it's outdated, it's more that you need to pre-select positions in some manner so you don't waste your time. If you are being paid X and a company pays their best employee X/2, but think they are paying 'really well', you're never going to not be wasting your time.
I admit it's not exactly applicable to salary negotiation, but IMO leading with a high number can help cement the counterparty's perception of your value. I think it really depends on what type of company (and what level of its food chain) you're applying for.
They may get more money total, but less money per unit time spent. Their ideal scenario is getting their commission instantly, even if it leaves some money on the table.
Why would I even bother giving them a number if they dont do it first? My way of saying, dont waste my time.
Additionally, remember that most independent recruiters work on some form of commission. It's in their best interest to get you more money because then they also get more money.