1. Except your model is missing an extremely important figure. Modern economies thrive off of the energy variable. This is not some missing detail, it is critical.
3. Energy is limited in the amount that arrives from the sun per day and the amount we have the ability to extract from the earth and the sun and the wind per day. The limit is evident by the fact you have to pay for it. If it were unlimited, your energy bill would be zero.
There does exist products on earth that while not technically unlimited can be practically considered unlimited. One such example is the air you breath. Energy is NOT an example of this.
2. No it is useful and highly practical. See here: https://news.ycombinator.com/item?id=26352352
3. Energy is limited in the amount that arrives from the sun per day and the amount we have the ability to extract from the earth and the sun and the wind per day. The limit is evident by the fact you have to pay for it. If it were unlimited, your energy bill would be zero.
There does exist products on earth that while not technically unlimited can be practically considered unlimited. One such example is the air you breath. Energy is NOT an example of this.