It think it's because it's very rare for developers to appreciate the value in building tools that they themselves wouldn't really benefit from. Regardless, it seems like a huge missed opportunity for the ecosystem as a whole to not make it an expected feature across the board.

Shout out to nostr:npub1hea99yd4xt5tjx8jmjvpfz2g5v7nurdqw7ydwst0ww6vw520prnq6fg9v2's Sparrow Wallet and nostr:npub1cvqlzvmjercdn0ypsmv8f7j9lge6ahsnueh5rparh53wuswftv4q49yjt3 for getting it right.