I bet you someone comes up with a fee-less POW based chain that doesn't centralise the mining. That'll be our little contest.
This sounds the same as someone coming up with a perpetual motion machine. "fee-less POW" probably breaks some fundamental laws of physics. I can't even finish an IQ test and see these things as obvious, cmon now. Maybe try again in a couple 100 years and we may have some mind blowing stuff which allows for very reduced fees at big volume transactions without compromising security and decentralization but certainly not "fee-less".
Fee as in financial fee.. no perpetual motion required, users will obviously have to put
something in (probably POW.. who knows.. maybe user based POCW)
T.E.T.O. (^^ above) has a fee-less POW based chain (DAG) that doesn't centralise the mining (AND no coordinator). It has it's particular issues ( seem like generic DAG issues ).. but it's pretty close. (Congrats to Monstererer2! for coming up with an original design)
IOTA has no fees, doesn't centralise the mining, and
almost works, but they have the Coordinator issue.
2 down.. and only an infinite number of different fee-less blockchain algos still to go..
..
It won't take 100 years to crack this nut
ps - I admit I am also working on a coin (fee-less) - aren't we all !? (win or lose - It's just too much fun)