Quora can be edited by anyone - it merely represents their opinion but rarely the truth. So don't take people too seriously on there. I agree to some extent with him, if bitcoin continues to have rising transaction fees and full blocks then bitcoin is indeed going to drop in popularity. However right now although teh problem is widespread it's not that big of a problem yet. Bitcoin is the first crypto and blockchain based currency. So if bitcoin fails, then it'll be extremely unlikely that others will rise and take bitcoin's place.