I mean you're right in a unabomber type sense (i.e. living in a log cabin trapping small animals), but if I wanted to build my own smartphone from scratch, my whole lifetime is spent extracting materials to build the equipment required for making the smartphone. Even if I somehow made the smartphone, I would have immediately violated some patent law.

Even if I were a globe trotting immortal, I cannot legally DIY most common electronics because of patent law.

Sure you can. You just can’t sell the item.