the only target price in the long run for bitcoin in terms of fiat is mathematically infinite and cant be nothing different.
Maybe 5 Million redenominated-$ (1 redenominanted-$ = 10000 $ , they will need to redenominate like shitcoiners to keep the price of bread at single digit prices) could be a medium/long target price for the next 4-5 cicle.

For purchasing power I think we could reach some reasonable limit, but still noone is bullish enough and all are applying bad euristics based on giving too much credit today fiat prices and other fiat indicators.
But seeing the past was always this the case: from Satoshi the goat himself that decided to define a "coin" at 100 million units because "based his my calculations when people will use it to buy things it will permit to express prices in single digit units like dollars" (something like that, I read it from recent-revealed email exchanges).
Then on every cicle there are all the crowd that predicts bearish scenario like "it will double in price because my tech analisys bla bla" and some crazy dude that say it will reach  10000000000 millions, I feel it, if you sell thats fine, more sats for me. I decide to be that guy from this cicle.
It will require time but will happen very fast, be prepared...