Trophies: Why don't they carry over?

Why don’t trophies carry over? I spent hundreds of hours getting all the trophies in BL2 and BL:TPS, I don’t really want to spend another 300 hours doing it again.

Transfer your character and do one more of everything. You’ll get most of your trophies pretty quick. The others that are not numbers based, well they might take a min. Also you already have the trophies once. Now you can double the trophies you have for one game by playing it across two generations. Makes sense to me.