Companies will not be buying aggressively forever. The fact that vast majority of them are selling now. Blackrock offload many of their accumulated BTC a long with Winklevoss and Saylor as well.
So companies who were accumulating aggressively could also sell their accumulated coins when it's needed.
While you may think that this is an actual argument it is a meaningless description of normal things, such as describing that a glass of water is sometimes full and at other times half full. The quoted events that you have described do not have any meaning and you can't derive any conclusions out of them. If you take a group of acquirers as the market participants, let's say that there are 100, there will be various different reasons for which they are entering a market. This is true of all markets, it has nothing to do with "the vast majority of them are selling". Some are entering, some are leaving. Bitcoin is the only asset in the world that is decentralized, with a fixed supply and this amount of utility -- you only need to have a small percentage of the buyers to want to indefinitely grow their stack and eventually you have a strong force that diminishes the supply.
We are not talking about any kind of supply shock nonsense, but we are talking about a gradual and long-term removal of coins from the supply that has strong impact on the price. At some times this impact is very strong and other times it is less, but it is still there -- this corresponds with the price fluctuations on the market too.
Bitcoin, in fact, isn't ideal for holding a certain amount (as those companies do) if the goal is to gain value.
I am convinced that you are a world class genius that has better investments lined up and which have made you a fortune by now.

More than 90% of people never make any money on any kind of investments, in started businesses the data is even worse. So surely Bitcoin is not ideal, people should do other things instead to lose their money faster instead of having financial sovereignty and value appreciation.

Will companies continue buying aggressively?
Could a handful of corporations end up controlling a meaningful share of BTC?
Yes and yes, and there is nothing wrong with that -- everyone has had and has the chance to acquire Bitcoin, it is for everyone including for entities that you may not like. You do not need that many corporations buying, you need a few that are buying for the sake of keeping it for the long term. Anyone who is thinking of doing a trade back to fiat is not applicable to this description. You gain very little when you realize gains in shitty fiat, you went out from slavery only to return back as a slightly richer slave. Genius move.