Nothing needs to happen really. Since bitcoin has limited supply and central banks will always print more FIAT, its price will increase in the long run no matter what happens.
If nothing happens and the adoption stays as it is or becomes stagnant and the incoming supply of Bitcoin from mining keeps on coming in then by the essence of the law of supply and demand then whether the price of Bitcoin will increase or not is dependent on how fast the inflation if fiat is. If the global fiat inflation is kept at low level then it is possible that the price of Bitcoin will not increase due to lack of demand in the situation I stated. Adoption is highly needed for Bitcoin price to move upward.
If you think a world war would drive crypto prices higher, I wouldn't be so sure. Probably the opposite will happen because crypto is a risk-on asset even though it is a better asset than FIAT. The biggest risk is the governments. If they decide to ban crypto, the price will tank to the oblivion. They are already in war with privacy and they are winning sadly. If they fight crypto, it doesn't look like they'll lose.
I also think that if world war happen, there will be less demand for Bitcoin because people will prioritize their survival and will focus on their basic needs.
One of the biggest contributions to the Bitcoin price may be governments accepting Bitcoin legally. The lifting of these bans by countries where Bitcoin trade is prohibited may also have a positive impact on the Bitcoin price. In fact, we can list many similar reasons, but even if these do not happen, Bitcoin will continue on its way.
Bitcoin, which has a limited supply, has always increased its price in certain cycles and will continue to do so. There may be many reasons for the price increase, but the main reason is Bitcoin itself.
Not just ' may be ' but that is ' sure ' because how can one invest on it if it's not yet legal on their country? And we know that an asset can only have a value if there is a demand for it. The lifting of BTC bans are also a sure thing that can help the price of BTC to rise. There are still other factors that can affect the price of BTC and listing them may not be necessary anymore because there are plenty of them. Not all times BTC's value is rising and not all times there is a reason for that but it's only normal because of the cycle that you mentioned there. It may look like the BTC's progress were limited but it's also an opportunity for the user.
The government accepting Bitcoin is a go signal for the people to jump into the market of Bitcoin. The acceptance will remove the doubt of people of Bitcoin being a scam. Aside from that businessmen and entrepreneurs will have the freedom to engage in Bitcoin in integrating them to their system without the worries of legal issues. So with the government acceptance Bitcoin is open for the masses to grab.