This would simply made my day if I was there during that time but for me it is a waste of time to try to even argue with them as they could either be a troll or just a person who isn't open-minded at all. Spending your time arguing with them is something that you must not really focus on as Bitcoin time and time again would just make them eat their own words just like how JP Morgan and other companies have changed their views towards the crypto industry and Bitcoin in particular. At least now people who have believe Bitcoin during the early days are sitting safely on a profit while these guys from 8 years ago might now be trying to buy Bitcoin at 60,000$ a piece.
Its not that their aren't open minded, they just don't know how to make sense out of bitcoin because conventional market is ingrained in their core that it challenges their beliefs and we all know that when people have their beliefs challenged, they tend to disagree with the facts and they disregard the potential of something.