Like i said earlier, the current intention is that generating a block would consume the age of the output used to generate the block, so your age is reduced to 0.
But even if the age was not consumed, i don't follow how that would be a problem?
If i was a POW miner with 20% hashrate, i would constantly have a 20% chance to generate a block, no?
Its a problem because it makes producing double spending blocks costless, forever. In POW this is not a sustainable attack.
It's simple really, if you don't mine a POS block, someone else will when the timestamp increments and their output gets lucky.
So, instead you mine a POS block with no transactions, thereby having the same effect as withholding the block?