So the fossil fuels we have today are all that there will ever be. When we use them up, they will be gone forever. The question is, therefore, which generation is going to have to deal with this reality? What a legacy to leave to our great-grandchildren, aren't we nice!
Yes, we are very nice, because at the same time we have been extrodinarily productive and inventive and thus have used the technology that the industrial revolution gave us to perfect the means of renewably harnessing the sun's energy and developing nuclear energy and eventually harnessing fusion energy as well as perfecting how to store and transmit that energy and the net of all those efforts will far surpass the use of relatively dirty fossil fuels as a means of sustaining our civilization far far into the future.
Quit beating yourself up about it, it's not only pointless, scientifically it's pretty silly.
Arthur