The algorithm BTC uses has been depreciated in favor of ASIC resistant mining protocols which prevent what we see with Bitmain and allow normal users to access mining rewards.

BTC ASICs are a case of failure to prevent centralization. Nearly every successor to Bitcoin has developed ASIC resistant algorithms to allow normal users to contribute to securing the network activity and be rewarded with newly minted supply for doing so.

Block rewards are nothing like savings interest because it works like an all or nothing lottery.

If the developer or an exchange controls 40% or even 10% of the supply, they have a significantly higher likelihood of taking newly minted coins which compounds further increases to their probability of increasing their control of the supply. All the while those who have less of the supply or are too poor to qualify for staking will not be exponentially increasing their wealth.