I think GPU mining will not die this year and in the next too. There will always be coins that can be mined. The question is to preserve and increase profitability. As for ASICs, after Monero and other alts have switched to other encryption algorithms, I think that ASICs producers will no longer be able to manufacture this equipment.
Monero had a very low miner reward. Hence the reason why it was profitable for like 2 days before evening out.
The issue is more with ETH. If ETH goes away then GPU mining will die. We won't be mining just to make 10 cents a day.
1) ETH goes POS - This is provably about a year or two away and not an issue
2) Bitmain keeps building more and more ASICS - Difficulty will keep increasing linearly
3) GPU manufactures keep increasing their production of GPUs - Difficulty will increase linearly
4) ETH price crashes and goes to like $50/$100 a coin. - Most likely to kill GPU mining fast