A crash perhaps, but not the end of GPU mining. With a faster randomx implementation soon to be released, gpu miners can move to secure the Monero network instead.
GPU mining will never die, but the question is if/when we'll ever reach the profit levels of ETH. It's a high-risk bet, which is why there would be a very high reward, comparable to when I mined my first Ethers in mid-2016 and could've been a millionaire if I build another rig or two and held the Ethers.