PoW Mining loses because of the constant increasing costs related to electricity and ASICS.
Meaning the price per coin has to continue to increase to cover the ever increasing network operations cost.
Also the problem that eventually the electricity required will be more than a small country.
![Tongue](https://bitcointalk.org/Smileys/default/tongue.gif)
PoS solves the electricity & asics issues, and is superior to PoW in those regards.
PoS problem is the ever increasing inflation , that is the result of PoS which always causes a downward price pressure per coin due to how PoS works.
The Solution is PoST , Proof of Stake Transactions
Which at the present time only
ZEIT is implementing beginning on Aug 11th, 2017.
The way PoST works is the coin has an Ultra Low Inflation Rate,
Ultra low for
ZEIT is .0005% per year, meaning less than 500 new coins will be created per day.
The network consensus is still Proof of stake, however the interest rate is so low , you can make more money per block by processing transactions fee than from the interest rate.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
As such , you can sell your interest rate & transaction fees income and never touch your principle.
However , if you do sell your principle you decrease your ability to compete for transaction fees in the future when the price of the coin is higher.
At this point in time , this is the best solution on the market.
![Cool](https://bitcointalk.org/Smileys/default/cool.gif)