I don't think ETH as a shit coin. But if ever eth surpassed bitcoin I see no reason quitting bitcoin. Why would I ? Surpassing bitcoin does not mean that bitcoin is useless already and I don't think it will last long. On the other hand just because eth surpass it, it is not enough reason to quit. Crypto is very unstable and we do not know what will happened next but knowing how good bitcoin is, it is possible to take its place as number one again.