Instead of transaction fees going to pay miners, its actually possible to instead store some of those fees in a fund on the network, which can be payed out to long term Bitcoin holders.
This is what bter.com does for their deposits. There is no reason why you couldnt do this on a blockchain as well.
If only we didnt have to pay miners for their costly task of confirming blocks - if only there was a more efficient way to do it.
Some PoS coin actually does that.
But there is little to no adoption to coin that offer interest to holders.
This is actually how PoS coins are mined. They earn "interest" when stakeholders hold their coins for a certain amount of time.
There is very little reason for anyone to ever spend their coins because it would result in them loosing out on this "interest" as a result the market caps for these scamcoins are close to none.