If it's so important, the interview invite should mention that casual wear is expected. Like it or not, most people take interviews seriously, and have been taught that you show you take the interview seriously by wearing a suit.

Tbh, people who blindly accept what they've been taught without considering the situation at hand don't make good engineers anyway (software or otherwise). It's not like programmers not wearing suits is some well-kept secret only accessible to the inner circle. Quite the opposite I'd say.

It's well known that programmers don't wear suits in the office in the SV. It's less obvious they shouldn't wear one in the interview either, because that's not a regular work day. It's not obvious at all to someone from a formal-dress culture like France (Italy? India?). Google's own AI recommends erring on the side of caution and wearing a suit for an SV interview. Yes, people should look up the specific company they're interviewing for... if it even comes to their mind, it's that obvious interviews require suits in some cultures.

If you forgive me the analogy, and assuming you're American, would you think of checking the etiquette of entering into a shop? In the US, the concept itself is weird, you go in, buy stuff, and leave. In France, you must greet the shopkeeper right as you go in through the door. In Hungary, you must wish the shopkeeper a good day in reply to their greeting. It's simple... if you know it's even a thing you should check.

Which is actually funny, because weren't we in the tech the people who aspired to “think different”? But then it didn't become think-different for the individual, but for the tech in-group against the square out-group. And since the world is becoming increasingly informal and any group worth its salt needs to differentiate itself, tech people might be the first to return to wearing suits and ties (or dresses) to work. I'd like that.

"Think different" was a marketing slogan used for Apple products from 1997 to 2002, back when Apple was aimed chiefly at video editing professionals. It was never aimed at techies.

As long as suits and ties remain the uniform of politicians and managers, I don't think techies will ever willingly adopt it for themselves as well.