Mining reward is another obsolete part. True reward for supporting Nxt network comes from services that use Nxt. Someone owns a currency exchange and mine blocks to keep his business running. Another one owns a shop and mine blocks to keep his business running. The 3rd person owns a software company that develops programs for Nxt-based services and mine blocks to keep his business running. Selfish miners (those who mine only to earn fees) should be "removed" from the system, they r not interested in success of Nxt and only want to cash-out. If a clone appears such the people will likely jump to another ship, they add very little value to Nxt. All this doesn't mean that we should get rid of fees completely, we still need them as a countermeasure against spamming.
Perhaps I am misunderstanding something, but this seems to idealistically ignore a different sort of selfishness.
If I'm running a Nxt-based business, I could either invest in forging myself, or just not bother, and expect someone else to do it.
A business that forges for itself, with minimal mining rewards, will be less efficient than one that just expects someone else to do it.
The free-riding company will out-compete the 'honest' company.