That rings strangely to me. I don't think I've worn anything other than a button-down shirt to a tech company (interview or otherwise) in the last...decade?

Somehow, I keep getting handed principal and director gigs and my peers are fine with me. I'm pretty sure it's OK, tbh.

I wear a shirt one/two days a month, but my default dress has been jeans+t-shirt for 20+ years working in the UK, and now Finland.

I'd "dress up" for an interview, but that's really what I think of it as. I think I average wearing a suit once a year, and that's usually for a wedding, funeral, or similar formal occasion.

I sometimes wear a button down shirt in winter, it's a surprisingly versatile piece of clothing. I tend to prefer ones that are a bit more practical than dressy.

Other than that, I've replaced t-shirts with polo shirts. Maybe it's just the t-shirts I buy, but they usually shrink weirdly and I prefer the pique fabric used in most polos. I also appreciate the collar (for protecting my neck from sun) and being able to unbutton to cool off a bit in summer. They also tend to last longer.