The thing is that good interface design is basically invisible, so most people, developers notwithstanding, take it for granted. In the late 90s, there were entire books published on using popular email clients like Eudora, but a literal child can figure out how to use, say, fastmail entirely through feature self-discovery, and fastmail has more features!

I also think the ego stroking borne from disproportionately high labor demand has given many developers a serious case of main character syndrome.