@Danthefan I don't think there is that much of a difference between before and after mangadex. Before mangadex we had Batoto, and I guess in the months between Batoto announcing they were shutting down and Mangadex becoming popular, some scanlation sites may have decided to opt into that kind of thing. I'd say that if anything, it's more prevalent now because of the issue some scanlation groups had with MD some months ago.
Also, I feel like you're misrepresenting the Light Novel Bastion situation a bit. Light novel translations are a bit different from manga is that there is just so much more to translate. With manga, you don't need to translate the backgrounds, the character expressions, the action, etc. Yes there is cleaning and typesetting, but I don't think anybody would argue that on average it takes a lot more work to translate light novels. Also, Death Mage chapters are fairly long. He also doesn't release chapters when the donations hit 200, as he gets donations faster than he can translate. It's not as if he has an archive of translated chapters and throws one out when the donations are high enough. His work is also pretty high-quality, so if people want to donate for it, that's fine by me.