I will regret why I have not putted all my bank fiat,land a, Gold and extra money into Bitcoin.
1 million is possible but Holding is so difficult. Market situation always differ. So no one can exactly know, what will happen tomorrow.
You should not regret about something that is not predictable or something that you do not even know about its future. You may regret it if you know that it will come true but you do not do anything for it. Even if you believe that bitcoin will hit $1M, will you put all your assets into bitcoin just because your "belief"?