OK, I'll bite. You raise powerful arguments on why Bitcoin could drop 99%. I'd argue it has a better chance of dropping 100% and I'll explain later how that could happen.
Here are my counterpoints to your arguments:
1) Bitcoin doesn't need to be a payment method in order for it to succeed. There are several other narratives that can apply- store of value, wealth insurance, portfolio diversification, passive income generator just to name a few. Gold has been a store of value for thousands of years and I have yet to see gold used for commerce.
2) I would argue that Bitcoin's value is subjective. If you are in a country with hyperinflation it may have a different value than if your native fiat currency is stable.
Bitcoin is worth whatever some person, institution, or government is willing to pay for it. What is the intrinsic value of an ounce of gold, a ten-carat diamond, a Picasso, a Dali, or a Beeple? People assign the value to these items just like Bitcoin has an assigned value.
Comparing Bitconnect to Bitcoin is not a fair or accurate designation. The tokenomics and white paper were completely different. There will be bad apples in every investment class. It’s similar to saying that one shouldn’t invest in any stock because Theranos, Enron, or Countrywide committed fraud.
3) Bitcoin mining does require a lot of energy. So does mining for gold. So does mining for Lithium. So does manufacturing vehicles that get leased for two to three years. If a country bans Bitcoin mining, then other countries are lined up to employ their resources. It's like arresting a drug dealer. Someone is ready to take their place the following day. China banned Bitcoin mining and it hasn't crashed the price 99%. As a matter of a fact, it will ultimately make the network stronger by diversifying the sources and requiring miners to be more eco-conscious.
4) There is no definition that a store of value can't lose value. Gold prices nearly halved after peaking at just under $2K. Does this mean it's not a store of value? Is currency a better store of value? Tell that to my grandfather who put a $100 bill under his mattress 60 years ago.
You state that: "generally, a store of value is anything that retains purchasing power into the future." I would argue that in its 10 years of existence, Bitcoin has proven that it's outperformed retaining purchasing power. If 100 million people see value in it, I'd say that it is beyond the tipping point of pure speculation.
5) Regulations will come. They will not tank Bitcoin's price by 99%. They will further legitimize the space and allow people to feel more comfortable storing their wealth with Bitcoin. The US is embracing Bitcoin as we see that members of the government and the financial elite are buying into it. Why would the government bite the hand that feeds them? Research Biden's second-biggest campaign donor. For all we know, governments may be huge holders of Bitcoin.
In my opinion, there are 2 main threats to Bitcoin. One will tank the price to $0 and the other could just turn off the masses.
1) Technology: If a hack, quantum computing, or bug could mint Bitcoin then the price could go to 0 quickly. We saw how fast Titan and many other exploited cryptos have fallen and to say this couldn't happen to Bitcoin is similar to saying that the Titanic was unsinkable.
2) Distribution: Bitcoin's distribution is heavily tilted in a small number of wallets. If these whales sold off en masse, it could cause panic and a death spiral in prices. However, whales have held strong thus far and liquidating doesn't make much logical sense unless you are trying to be the first person at the exit when the theater catches fire.
