Probably the reason why people are not using bitcoin as payment because of its volatility. If you buy a shoes worth .01 btc or roughly $60 and tomorrow that .01 btc will be worth $80 so that you just paid $20 over the price of that shoes. So that won't really mean good for you. So i think bitcoin being so volatile makes people not want to use it as payment.
Proceeding from what you said, it turns out that bitcoin is only then massively used as a means of payment when it reaches its maximum price. That is, when this happens, no one can say. In other words, bitcoin will not yet be used massively as a means of payment, that is, as virtual money, because everyone is still hoping for its rise in price. However, when people are convinced that bitcoin will not grow in price, it can only be if it falls very low in value and practically becomes useless to nobody. Hence the conclusion - bitcoin will almost never be used primarily as a means of payment, but only as a speculative means of accumulating value. This is a dead-end option for its development, because in any case it will lead to the rupture of its bubble, it is inevitable.