You'd probably be wrong. Cultural fit may be important, and you don't want to get strange looks on an interview. At the same time the company still might be quite good - as in "early Google"-like good.
I've hold for a while the attitude that if a company pays attention if I'm wearing a suit in a job interview, I shouldn't get a job there.
I don't have anything to complain about that attitude. In retrospect, it saved me from quite a few bad situations that my inexperience would make me accept. But things changed and it does not apply anymore (am not even technically working on IT anymore).
In all seriousness, are suits still a thing for interviews? I don't remember the last time I heard of a company that was anything more than business casual dress (and lets be honest, many firms are much more casual than that).
I'm not in industry, but in CS academia interviews seem to be the one holdout where people do usually wear suits. People attending conferences don't (except in Asia), professors don't, the department chair doesn't, the interview committee themselves probably won't either, but there's a ~70%+ chance that someone interviewing will. Or at least a sport coat and slacks (I guess not technically a suit, but close enough). You probably don't really have to, but people tend to err on that side for an interview in an unknown setting.
But for the tech jobs most people want, it's a really bad idea to put a suit on for a interview.