It is, but self sufficiency is nearly impossible. To pay for tools and machines, electricity and water you would need to sell parts of your produce. That is hard if you do not scale up to a level to compete with highly advanced industrial agriculture.
Of course you could scrap the electricity and get your water from the nearest river, but I doubt many people would want to put up with that.
Self sufficiency is possible if you are given 5-10 acres with no taxes. Even then eventually you will need to trade your animals with someone else just so your breeding stock doesn't get inbred too much.
Most people wouldn't want true self sufficiency if they could have it. I admire people who "go into the woods" for years (they are generally more hunter/gathers than farmers); but even as introverted as I am, I still like to have a larger group of people around me.
Wooden hoes. No modern medicine either. You have to make sacrifices for true self sufficiency.
For clothing, you grow it. Between Flax, wool, furs, and cotton you can grow something anywhere (except near the poles). Having to grow clothing and shelter more than doubles your needed land area in some places.
OK, but then, how do you make your wooden hoes? With wooden tools? Wooden knives and saws? How do you sew your clothes? With wooden needles? Sooner or later, don't you need some metal somewhere? If you don't have it, aren't you essentially living a Stone Age existence?
Of course you could scrap the electricity and get your water from the nearest river, but I doubt many people would want to put up with that.