DIY "HiFi" cables - and why I don't trust BJC and the likes

After watching these two youtube vid below, I suspect a lot of online so audio cables companies are like these.  They basically use off-the-shelf spool of wire that you can easily purchase from HomeDepot or PartsExpress and dress them up nicely with fancy jackets.  I think BJC falls into one of these categories although for their credit, they don't charge a lot of money.  

I don't mean all audio cable companies are like that.  I do think some well established companies such as AudioQuest, QED ... actually have some real engineering going into their products.  For example, QED has a very unique geometry in their cables that you can't get from off-the-shelf.  It's just that there are too many online companies that give the cable industry a bad name.  

https://www.youtube.com/watch?v=YuxK-HQGvkI
https://www.youtube.com/watch?v=nyEexBJoR-E