Is "fee higher than block reward" attack possible?
An attack like this is possible, it is just a way to profit off a 51% attack. However you must remember several things:


if a miner controls less than 51% of the hashpower, then chances are they will not be able to catch back up to the network after mining the malicious tx, so the honest network will prevail as the longest chain
if a miner tries the attack but fails to succeed, they will have wasted a lot of resources in doing so (opportunity cost). Compare this to a more guaranteed profit of not being malicious
if an attack like this succeeded and users noticed, it would hurt the security of the network, and thus coin prices should be expected to fall. So the miner has undermined their own investment. 


If you hunt around online, I have seen a simple formula for determining the value of transaction vs the number of block confirmations to wait for before considering the tx ‘final’. Your line of reasoning is correct: for larger transfers of value, the wait period should be longer, so that the potential reward of malicious behaviour is outweighed by the reward of honest mining.