This particular signal also indicates a willingness to set aside one's individual ego in order to assimilate in the workplace, which is especially valuable to the companies demanding developers abandon good sense in order to push AI adoption.

If we want that signals to not be "a suit", it will need to be something else. But one advantage suits have is that they have served as that signal for so long that they are extremely accessible: just go to the thrift store, take what you find to a tailor and you are good to go. It is very easy to look up what is expected, and there are a variety of ways to trade money for effort or vice versa.

The highest-paying developer jobs have always expected programmers to wear suits to the interviews: in a recession those things previously only top payers could demand cascade down market. I don't love it, but I don't think this prediction is wrong.