Vosk provides a lot of good information on youtube constantly, I do keep watching every video he puts out and I have seen his latest with 6800 gpu's as well to see what it will be like from a miners perspective.
However you guys have to realize one thing, this guy spends a lot of money on testing these things out and he made some profit obviously from mining and even these passive incomes but he also made a lot of profit from youtube as well since he is providing this service, hence I am not sure if we can call his success only due to mining, youtube played a part in it as well, without youtube it would be making a bit of money but maybe not worth all the work he puts into it.
You can calculate all these information yourself if you want and you can see how risky or riskless it could be, nothing unheard of in the video.
Nah, it's hard to believe such passive income nowadays because I believe only early investors are gaining this passive income that they're talking. He may be spending a lot of money from there but I highly doubt youtube isn't a huge part of this passive income since most of these people are using the social media to create tons of content just for the sake of views and ads.
Altcoins is somehow a pump and dump that no one could maintain a passive income but not unless they were mining. Although mining also is not as good as the earliest miners since the mining difficulty keeps growing each day.
