Isn't that how the economy works? Especially for a volatile asset like Bitcoin? Obviously it does!
When a big company like BlackRock buys Bitcoin, they source it from the miners and not from the open market. So as a common people we do have zero control over the transaction. So there's nothing to regret.
If you have a long term vision for Bitcoin, start averaging your buying price from today onwards. Or there will be regrets later.
There is something fundamentally wrong with your calculation if we consider that Bitcoin miners currently cannot mine more than about 900 BTC per day (reward 6.25 per block in an average time of 10 minutes per block), along with the fact that for some 6 months, that reward will be reduced by 50%. This means that currently around 27 000 new BTC are created per month, but also that each miner sells only as much as he needs to cover the costs, and they keep a part like everyone else and wait for the right moment.
It may be true that we cannot influence when and how much BTC someone will buy, but each individual can at any moment say
"my BTC is not for sale", and that means that we can influence the market and the price to some extent. In addition, Bitcoin has a much higher value than the one shown in fiat, because max supply is a fact that gives it that one extra value that nothing else that wants to compare with Bitcoin has.
Banknotes will always be printed, coins minted and gold and diamonds dug out of the ground, and in less than 10 years 99% of BTC will be in circulation, and even if someone wants to buy only from miners, they will only be able to buy very small and limited quantities.