Bear in mind that this basically disqualifies people like JubyPhonic from what she's doing, unless she is asking for permission every time, then pardon me. She also has a patreon, and whilst that's not monetizing things from her covers directly, it's still a form of obtaining money. And, don't get me wrong, I think monetizing simple singing covers is wrong, and monetizing remixes/arrangement covers should only be done with a permission and some kind of agreement between the artists.
Personally, I have two last translyric projects on which I've worked for months, and after that I don't intend on continuing since I'll most likely be focusing on original music anyway. DECO*27 has maybe seen my (now deleted) English cover of Streaming Heart since I uploaded it on his official FB (which I know is not maintained by him, but I think he has an idea of it). He didn't seem to mind, but I can ask him about my next cover.
Whilst bodytemp claimed this is a Japanese universal cultural and legal law, it doesn't mean that all producers are really angry at you for covering a song or writing translyrics for it. Although I'm sure all of them will be mad if you monetized those, obviously. To me, it's odd that they don't give out off-vocals with only permission or make you pay for them if you really need to be allowed/authorised to do a cover.
Additionally, does the translyrics thing apply to normal translations, too? I understand producers don't want their songs to be misunderstood, but at the same time, they are basically kicking the Western fandom out. We're not allowed to interpret their song, whether it's by trying to understand the lyrics or making a cover, and I rarely ever see a Japanese producer putting out an English translation or translyrics or even caring about trying to contact some Japanesr to English translator. Of course, the song is their property and I fully agree that they do have a complete control of what happens with their song. They also have a right to not care about the Western fandom. In short, we're the only ones losing. Although they could potentially be also losing fans, although they may not care about it if all they care about is obtaining money from their music (which is perfectly fine, some people use that money to support themselves after all).
And on a side note, since Japanese producers expect the Western fandom to have really good Japanese to understand their songs from-word-to-word, can we expect them to understand English if we're asking for permission to cover their song? I don't mean this to be an aggressive question, as it's a genuine inquiry. This is because if a Japanese producer messaged me in Japanese about any of my covers, I would make sure to get someone to translate the message for me.
On piapro, we're told we can do whatever with an instrumental as long as we don't monetize it. So what has changed? It appears that nothing has. And yet only now the apparent producers' wishes (which may be not representative of all producers mind you, unless someone has done the inferential statistics so that bodytemp's findings can be generalized to all producers) are revealed. Primarily, I'm surprised that producers don't make any announcement or/and not contact people who made a cover they don't like to take it down. If, like bodytemp claimed, making undesirable covers/translyrics were an issue, asking permission would become an unwritten rule. But instead, producers complain to themselves and friends, which in the end makes no change to the whole situation. And because of that, writing translyrics and making vocal covers exists the way it does, hurting producers that don't say anything about it.
As for a conclusion, I'd like to highlight that I'm certainly against monetizing covers and I will from now on ask for permissions to cover songs, but producers not saying a thing until now is absolutely weird to me, since the culture of writing translyrics and making covers without permission has grown so much that one single post on an UTAU forum cannot stop it. There are no statistics to show that what you say is true, bodytemp; only a qualitative analysis which may not be appropriate to generalize to the whole population. So put to all of my point simply, it's a bit late to suddenly stop the whole notion of creations, but that doesn't mean we can't change for the better.