I was able to get in contact with a long-time devoted Finnish folk believer and asked him who the last tietaja was. He says one of the last high profile one was Anni Polonen, but there were others who quietly continued the tradition longer. He explained that the last tietaja who was fully capable of the traditional gifts such as entering an escatic state probably died in the 1960s, as Siikala told him she met one in the 60s. This must have been what she was vaguely refering to in her book. It seems whats going on is that scholars made contact with such people, but it tends not to get mentioned as much, which Im guessing is because less and less traditions were present with these late practicioners. My contact also explained that the families of these late tietajas have also preserved some of the old art to modern times, but again they are quiet about it. The wiki page on Anni Polonen says that her son carried on at least some of her practices into the 1990s, and her granddaughter studied history in university, focusing on her grandmother's profession. I was also warned to be wary of the many fake gurus.
https://fi.wikipedia.org/wiki/Anni_P%C3%B6l%C3%B6nenhttps://fi.wikipedia.org/wiki/Aappo_Jurvelinhttps://fi.wikipedia.org/wiki/Aali_PitkonenThen earlier today while googling, I hit a jackpot; an article that had audio and video recordings of the old sorcerers. It includes rites being practiced in the 1930s, and a 1965 TV special on spells and magic that interviews some elderly practicioners:
https://yle.fi/aihe/artikkeli/2016/03/1 ... arannuksenThe same site had yet another jackpot article, this one had an audio recording from 1905 of the Karelian poet Petri Shemeikan reciting a spell of fire, a 1965 video of the witch Elmi Tsokkinen in a studio sauna with a realistic baby doll performing a healing ritual on it while chanting spells that mention Vainamoinen, and a 1973 video(!!!) of the elder Karelian Jaakko Köpönen performing a spell against cuts from iron. Both Elmi and Jaakko were from the Karelian town Suoyarvi. About half of these videos are available to download, and frustratingly the coolest ones are not available.
https://yle.fi/aihe/artikkeli/2016/04/2 ... n-jaljillaAnother article from the site has video from 1976(color!) at a midsummer festival, and another from 1977.
https://yle.fi/aihe/artikkeli/2011/06/2 ... nustaikojaThe 1973 video with Jaakko Köpönen performing the spell is cut from a longer video about Karelian traditions and how they are disappearing. He also sings traditional poetry in the video. There is also an interview with the elder poet singer Vasili Peiponen. Apparently back then young people were already only speaking Karelian at home with their families.
https://yle.fi/aihe/artikkeli/2015/05/2 ... alaisuutta