While the pie chart may be alarming, let's not jump to conclusions about Bitcoin's failure just yet. It's important to remember that the strength of Bitcoin lies in its decentralized nature. As long as individuals continue to hold and transact with their own keys, the true spirit of Bitcoin lives on.
You're right, its strength and "robustness" does rely in its decentralized nature, but what that's truly the question. What's the threshhold? 50%? 60%? What if more than 70% of the total supply are held in the vaults of trusted-third-parties?
Currently, these are the largest centralized entities that HODL Bitcoin in their vaults, it's probably growing,
https://bitcointreasuries.net/?maximized=treemapIt could continue to get worse after legacy asset managers like BlackRock start buying and HODLing Bitcoin in their vaults too.