What do you think? Is it necessary or possible to control a decentralized cryptocurrency or not.
The very fact that something is decentralized means that you cannot fully control it and there is no central authority that has the power to limit or control it.
I do not believe that is how the decentralized aspect of Bitcoin network works. Changes in the system are only possible through the collective decision by the majority of Bitcoin nodes, not by Bitcoin whales.
No, that is incorrect. The system can be decentralized forever.