(Forgive me if I make any mistakes, this is my first time using a forum
This is also going to be a LONG post, apologies in advance!)
These are
still going today and I can't find any other posts on the internet discussing this anomaly as an outsider looking in. It seems odd for it to go so unnoticed by the general public when it's been so rampant for so long.
I'm also going to mainly focus on a specific niche of the "Ievan Polkka" fixation, the "fanloid" videos. I'm not sure if OP meant
those or not, since most of the videos they linked are unavailable, but it seems relevant enough to the thread.
A simple search of "Ievan Polkka fanloid" leads to seeing hundreds and thousands of these videos on YouTube. This channel gets top results during a Google search, as an example:
The most recognizable thing about this subset of videos is that they use the Ievan Polkka PV from Project DIVA Future Tone, but with different modules (or modded characters) and video effects to represent the "fanloid" in question.
The audio tends to be more diverse - most, if not
all of them, use an already existing cover with audio effects added on like pitching or voice changers. Many of the creators do not credit the audio source, with people in the comments having to ask or guess the voice used. I've witnessed someone ask for credit on one since it used their audio, and I've seen another legitimate cover creator complain that their covers get stolen, so circumstantial evidence suggests most of the audio is stolen from legitimate content creators.
Any "new fanloid" created by these Ievan Polkka channels is formulaic, doing the same old shtick of recoloring the Project DIVA PV while using a module and adding an edited version of a stolen cover. Often times the editing is very amateur, with simple effects and sometimes even rough cuts of swapping out audio. The comments are always filled with simple praise or poor typing, with some channels responding to comments with a barrage of emojis, which leads me to believe that these are all in fact children creating and reacting to this type of content.
Kids don't have the knowhow to credit people or make more original content, and have a tendency to fixate on stuff, which explains a lot. I believe some of these "fanloids" may be created at the request of commenters as well, which means that a small part of the unoriginal nature may come from simply fulfilling requests as easily as possible.
I'm personally bummed that these kids all flocked towards the concept of a "fanloid" since it muddies the waters when trying to seek out fanloids that have more effort and staying power put into them than just recolors and stolen content, but that's neither here nor there.
The only exception to them being children seems to be when they grow out of stealing content, but still have the Ievan Polkka fixation, and sometimes move onto creating legitimate original covers and UTAU voicebanks. I assume that many of the people who credit audio sources are probably older kids since they're showing a degree of responsibility, and I've seen someone in their early 20s call themselves an "Ievan Polkka weeb" and create more original content that still focuses on the song- this person also refers to the trend as the "Ievan Polkka community" and has voiced an intent to save it from the sea of poorly-made content by producing more legitimate content, though I believe this is a losing battle.
As for an origin to it all...
Searching "ievan polkka fanloid before:2017-01-01" and "ievan polkka fanloid before:2018-01-01" lead to two
very different results. Before 2017 there is not a trace of these videos, only the type of "fanloid content" that would have been prevalent during the early 2010's.
Before 2018, however?
Tons of them. The floodgates had been released by that point.
By narrowing my search to each month in 2017, I believe I've found the "origin" of this trend:
This was posted on September 22 of 2017. Although the video features Zatsune Miku, a fanloid already well-known within the community, the channel KathCyna would go on to produce videos featuring the formulaic and unheard of "fanloids" that are recognizable to this trend, making them the pioneer of this niche little genre.
(Interesting note: If you look at this channel's uploads, the Ievan Polkka fixation was there from the very beginning, with stolen audio and continuous rehashing of the Project DIVA PV, but the fanloid aspect didn't come until later.)
In November, another channel would post Ievan Polkka fanloid videos, but these did not feature the Project DIVA PV, only MS Paint art of the fanloids. This channel seemed to have posted low-effort fanloid content since October, and the Ievan Polkka overlap came after, so this is possibly coincidence.
December seems to have been the point at which this trend started showing up in full, with multiple channels putting out videos featuring Project Diva PVs, stolen audio with pitch edits, and fanloids that nobody had heard of before. Over 6 years since then, and still going! Incredible.
I suppose with all the low-quality content within the classic Vocaloid and UTAU community, like poorly edited pitchloids, plug-and-play covers and MMD videos, MMD models stitched together with uncredited assets and motions, etc., something like this was bound to happen. It's just odd how very specific it is- like a divergent evolution of all those things that ended up creating its own genre, with dedicated channels and playlists full of such content.
Because so much of this stuff was seemingly made by children and I've described it in a somewhat insulting way, I will clarify I don't think poorly of these children, and I don't blame them for creating this type of content. It's just very perplexing that this "Ievan Polkka fanloid" trend is so prevalent, and unfortunate that so much of it is unoriginal and even stolen.
Yes, kids will be kids, and kids will trace and copy art they found on Google and decide that they want to be a Vocaloid so they make their own fanloid using three screws and a wet sock. I just think if these kids started creating more original content, like making their own art for these "fanloids" or figuring out how to use UTAU, it would benefit them in the long run. Even if it wouldn't be "good," it would show potential, and they could develop that skill into something great, something fulfilling for them. If it ends up being quality content that's entertaining for others, that's also a plus.
TLDR: It originated through a combination of kids fixating on Ievan Polkka, making fanloids, and stealing audio for pitchloid-esque stuff, leading to the trend forming in late 2017 and children keeping it alive today, pumping out content in a formulaic manner.