And many can not be totally decentralized in the world, bitcoin is no different.
You do have a point there, mate. No matter how hard we try, there would be no such thing as total decentralization. Any kind of cryptocurrency, will face the same issues as Bitcoin.
Thus, it would be important to try to minimize centralization as much as possible to ensure a strong network and good democracy towards the success of a specific blockchain for years to come.
Maybe someday, ASIC costs would become cheaper, greatly maximizing the chances for entry to anyone interested in participating on the security of Bitcoin or any other cryptocurrency's network.
I wish that Bitcoin would become great again by allowing anyone to easily mine coins even if they don't have access to an ASIC. Nevertheless, if Bitcoin becomes more adopted by people across the world, it could spread out its hashrate even further to increase mining decentralization. Just my opinion.