If there is plenty of oil and coal already in the pipe to fry the world, why even worry about peak oil (or hope for peak oil to halt carbonization of the world}? We need to address the carbon emissions, probably by banning them or pricing them high enough to change behavior.
Nice to see you here! I think peak oil is still relevant, in that I think we need to enact a response that addresses both climate change and peak oil together - no matter which one bites us first. And that means we need to prioritize reducing use of fossil fuels - both to prepare for the inevitable day when they will not be readily available, and perhaps more importantly because they are frying the world, as you say.
I think you are correct in pointing out that just hoping or waiting for peak oil itself to reduce the amount of carbon burned is not a good strategy! Not only because climate change is affecting us now, but also because it will be much more painful if we don't transition off of fossil fuels before they become unavailable.