Remember, the miners get to keep the transaction fees, so in the future even after all the bitcoins are minted there will still be some reward for miners. But transaction fees are dependent on usage, so if nobody is using bitcoins then mining will have no reward.
Are there any projections out there as far as when transaction fees will make up a greater share of the mining profits than the remaining bitcoins?
Nothing accurate. It depends on any change to how many transactions will fit into a block - which is an ongoing debate.