I think showing grace was the right way to do things. It preserves the value of all the effort he put into it. When you work on things that long they are part of you. Like your baby, you don't toss them aside carelessly, it's painful to do that I'm sure.
Well done for Tim for being one of those guys that worked so hard for others to benefit. Tim, you've done something you can be deeply proud of forever, no matter how it ended.
I don't know why owners/maintainers show grace like this.
For me; I would say I'm done and hand it over or just archive the repo.
Hope Tim finds a measure of sanity after he steps down.