The whole "we needed to rewrite everything" is complete nonsense anyway. There are THREE patches posted on the issue tracker over a period of more than 10 years. They work well, too; people have maintained out-of-tree patches for this (IIRC there's even an AUR package for it in Arch Linux).
GTK developers simply chose to ignore this. They explicitly solicited patches in that issue and then ignored those patches. Not "this patch needs work", just nothing. I get that reviewing patches is work too, but you can't solicit patches for an often-requested feature and then just ignore them. Well, you can, obviously, but it makes you an asshole. When a few years later someone pointed out the latest patch on GitLab it got shot down with a shitty snide "we're not going to look at random patches" comment and had the topic lock (it was on the old/now-deprecated BugZilla).
But hey, got to have some historical revisionism to justify your shitty toxic behaviour towards volunteers and users.