My question is simple. Does the miners' fee include some risk for the possibility that their blocks don't make it into the long-term chain?
Does the miners' fee include some risk for the possibility that their blocks don't make it into the long-term chain?
The miner's fees are fixed. The miner can't charge an insurance fee and the network does not reward failure.
There is a block reward that depends only on the current block height. This is a fixed amount per block that halves approximately every two years.
The miner also collects any transaction fees that people have chosen to include in the draft transactions they created. The miner can't change these. The miner can only choose which transactions to include in their block. Transactions with low fees are likely to be chosen last and therefore take longer to confirm. This gives people an incentive to offer a fee that will ensure their transaction gets confirmed in whatever time-frame they are prepared to wait (modulo about 10 minutes). Thus the transaction fee is largely determined by supply and demand.
These collected fees are non-spendable if their block doesn't get accepted. So miners have no mechanism in the Bitcoin protocol to collect from transaction creators any kind of insurance that pays out if their block is not accepted.