Zero conf was never secure. Many did demonstrate double spends long before RBF was thought of.
Still, that argument was made against RBF and was enough of a hindrade to consensus that RBF was made opt-in. And it still is. So you are absolutely free to accept zero conf transactions, and take the risk, as long as you don't accept those who flag for RBF. Most wallets won't even make them by default (which in my opinion is stupid with the fees we have today).
The argument for a golden age before RBF isn't a good one. It was never reliable. And what little reliability it had is unchanged.
Still, that argument was made against RBF and was enough of a hindrade to consensus that RBF was made opt-in. And it still is. So you are absolutely free to accept zero conf transactions, and take the risk, as long as you don't accept those who flag for RBF. Most wallets won't even make them by default (which in my opinion is stupid with the fees we have today).
The argument for a golden age before RBF isn't a good one. It was never reliable. And what little reliability it had is unchanged.