if Bitcoin were to reach $500 again today, do you think people would still be willing to buy?
Whatever the price of Bitcoin, people will keep buying. If there is no buy and sell, Bitcoin will have no price. Increasing to $500 is just a sign that the demand for buying is increasing very significantly.it would likely have ruined many people's investments and life savings, considering those who bought in at $10k, $20k, or even $100k.
How this can ruin people's investment?If the price increases to $500, people will get huge profits. Moreover people who bought at $10k, $20k, $50k, etc.
it would reinforce the skepticism of those who don't trust digital currencies due to their perceived unreliability. So, if it happens, would you still buy it?
Honestly, this statement is confusing. 
When there is bigger demand on Bitcoin, it means it is reliable thing. So far, Bitcoin always growing, the price keeps increasing.
Anyway, sure I will keep buying more and more Bitcoin.