Re: How the Bitcoin ETF could actually tank Bitcoin's market value
And what if the first impression of millions of mainstream potential investors in Bitcoin is that it's just a super-volatile asset that only seems to go down in price?
Nothing, they leave Bitcoin alone so bitcoin can go back to only going up in price 
Um, you understand that if Bitcoin is "left alone" by investors, it goes... down in price, not up, right?
In a sense, you just made my point for me: that the ETF will introduce Bitcoin to millions of mainstream investors, who will just view it as another instrument whose job is solely to go up in price, and they aren't going to find any meaning behind it when except that it is not any more "private" or "decentralized" than any other ETF they buy from their licensed brokerage.
And I don't know how much more I can say to "prove" that Bitcoin is not effectively decentralized for almost all of its users except to say that nobody I've ever known personally who has invested in Bitcoin or other cryptos actually physically hold their own private keys. They all use it through some app or brokerage like CoinBase, which means it's no different than their bank account.
Put it this way, if everybody who currently holds positions in Bitcoin and don't physically hold their private keys "left it alone"--in other words, sold their positions--then the price of Bitcoin would probably drop by a factor of about a thousand...