And I mean, we all spend all day editing test messages and comments and files on non-ECC hardware, yet bitflip-induced corruption is rare enough that I can't say that I've witnessed a single instance of it in my life, despite spending a good chunk of it looking at screens.

It's just not a problem that occurs in practice in my experience. If you're compiling the release build of a critical piece of software, you probably want ECC. If you're building the dev version of your webapp or writing an email to your boss, you'll probably survive without it.