My most realistic bull scenario, is that there is a split of reserve currencies, and minor nations begin to adopt BTC for international transactions. BTC takes on a "petrol dollar" type of quality, and you hear of nation states using it for larger transactions. It becomes globally recognized store of value for savings across first world nations, and third world nations populations use it in lieu of bank accounts. I think with this it takes on a large enough market cap to get nearer the $500k a coin mark.
Worst case scenario is that it becomes so banned by first world nations that its only held in the fringe, there are only "rogue" states that use it, and it never surpasses a few trillion in market cap.
So I think most would say I'm bullish either way haha.