Your post hit a nerve for me...I'll leave it that, however I will relay a bit of an incident that I was involved in that is eerily similar to your post.

The very last call I went on when I was a firefighter was this exact scenario. A farmer flipped his tractor over the side of a dirt path on his property.. The ROPS on the tractor initially saved his life but he was not able to get the seatbelt undone and was left hanging upside down. His daughter found him about almost 2 hours later and we were dispatched, however it was too late to save him despite our best attempts. We noted there was a lot of blood and cuts and torn nails on his fingers and shirt, our chief told us that these were caused by the man clawing at the seatbelt in an attempt to free himself...

I recall that in our discussions afterwards, the same mention of having a seatbelt cutter available to him could of possibly saved the man's life.