Well, in some cases people are just ignoring laws because they know enforcement is lax.
Technically, I need to get a permit to cut down _any_ tree over 5 years old more than 30 meters from my house. Nobody does this, and the law is unenforced, but I probably wouldn't put up a video of it for fear of attracting attention.
I also should have tried to get a permit for my daughters' playhouse - _clearly_ not an inhabitable structure - because it's in the curtilage of a protected structure. But I didn't.
Recording things and putting them online invites complaint from busybodies though.
If we're just going to make up loosely related metaphors, here's another one: it's like posting a car review composed of nothing but accelerating the car on a highway.
You consider these videos fantasy, for others they may be instructional. That everyone watches popular videos with exactly the same perspective seems pretty unlikely.
The creator isn't doing a 'review of building a log cabin in the woods'. Building codes vary so widely from country to country, let alone city to city, and then rural area to rural area, the chance that it has any relevance to you is small. TBH if the video started off with building permits I highly doubt many people would stick around.
You may look at this video as instructional, and that's probably okay, but it definitely wasn't created for that purpose. So its up to you to do the research on the omitted content.
The answer to 0 is "call your local permitting office". For real, these people are usually really nice. At first they will probably talk over your head because most of their work is with seasoned developers but as soon as they understand you are a noob they can usually talk you through what you need to do.
Or they're annoyed you're wasting their time by trying to pull permits as a homeowner but can't outright say that they expect you to not get permits and that they don't care.
Purchasing land, getting building permits, etc. are not part of the fantasy, so they are never going to feature in the video.
It's like saying "these videos of hot bikini models oddly omit all the dieting and exercise"