"Self sufficient" where you buy things from the supermarket is just greenwashing cosplay. Just like a "self driving" car where you can't take your hands off the steering wheel.
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.
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.
Where do you get the iron for your implements? Or are you going to use wooden hoes?
Where do you get medicine, when you need it?
Where do you get clothes?
Et cetera.
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.
Our agriculture (Ger) is completely dependent on workers from abroad. If you send the average office worker on a field, he will probably collapse after a day or two.
Friends of mine have some chickens and that alone causes so much work everyday... They give away the eggs which is nice for us. Selling them wouldn't even pay for the fuel to transport them anywhere. Same with most other kinds of produce.