The elephant in the room is still the same, what will bitcoin (or any blockchain for that matter) be used for besides speculation at the moment? If the ETF's and the MicroStrategy's of the world continue to acquire and hoard btc, there will be a speculative liquidity issue which should drive price higher and higher.
On the flip side, if big money hoards a large percent of a blockchain, users and developers might flee as it becomes no different compared to centralized currencies.
You've raised some valid points here. It's true that a lot of the current interest in Bitcoin and other cryptocurrencies is driven by speculation. However, it's also important to remember that many new technologies go through a phase of speculative interest before their practical applications become clear. The internet itself is a prime example of this.
As for the hoarding of Bitcoin by big players like ETFs and MicroStrategy, this is indeed a concern. However, it's also a sign of the growing acceptance of Bitcoin as a legitimate asset class. The fact that these big players are willing to hold large amounts of Bitcoin shows that they see long-term value in it.
The comparison to centralized currencies is interesting. While it's true that if a small number of entities control a large percentage of a blockchain it could resemble a centralized system, there are key differences. For one, the transparency and immutability of the blockchain are inherent features that set it apart from traditional centralized systems.
Moreover, the beauty of blockchain technology is its decentralization and the fact that it's open-source. If users and developers are unhappy with the direction a particular blockchain is taking, they have the option to fork it and create a new path as we have witnessed numbers of forks.