This spam wouldn't be so profitable anyway.
In the actual situation, how can you be sure the block will be mined by you? Miners would be paying thousands in fees but without any guarantee that they will mine the block and receive everything back to them.
If most of the blocks are mined by one or two individuals, and they are sure that they will receive everything spent in fees back, they would also be sure that the next block will be found by them, which means that we wouldn't be safe from malicious miners anyway.
That way, malicious miners would be no longer interested in including lots of txs paying lots of fees on a block to raise the "recommended fee", because they can't be sure they will be lucky and mine the next block to get the fees they paid back. It would no longer be profitable for them.
Neither they know if they will be the ones finding the current block.