If a fee market breaks down because miners are not acting rationally,
it seems that that could happen with or without a blocksize limit, and
generally to the same degree.

Example:  Assume a pool/farm with 20% hashing power that solves 1 out of every
five blocks and will include anyone's transaction regardless of fees,
this would cause a problem with a fee market regardless of whether
or not there was a blocksize limit.

although i suppose it would be worse with no limit, since everyone
would have room to get their transaction in , in the irrational miner's
block vs waiting longer.