A piece of paper with words written by hand (no printing).
Forget hardware wallets for COLD storage, flash memory loses its data after a few years. A hardware wallet adds security when moving your funds, so its good for HOT wallets.
I don't agree with you. I think that paper wallet isn't safer option than hardware wallet. Paper is very vulnerable material and you have to protect it very well. And even if you keep it safe, text with recovery seed may become blurred after few years.
Yes, hardware wallet isn't perfect too. You simply may drop it from table or spill coffee on it and dame device. But with hardware wallet you need to write down recovery seed and it will work as 2 layer security.