The mortgage gives you a roof that far surpasses the comforts of what would be a royal palace for an uncontacted tribe. If you're ok with a lifestyle on the level that they get (with hard, dangerous work), you can have it quite easily in today's society.

Go far enough into a forest and you'll likely be left alone when you build a primitive hut, except that now an hour of work buys you a lighter, a knife of unachievable quality, a pack of pills that save you from dying from infection, or "firewood" (a propane cartridge) for days.