TL;DR: Centralization in the network is definitely a concern, but I don't think these numbers are scary.
Of course, the goal with staking pools is that they'll decentralize the network and encourage many stake pool adopters. Actually, Cardano has a formula used to determine block rewards and you'll notice that it reduces rewarding blocks to stake pool operators (SPOs) drastically after a critical value, determined by the number of ADA that will saturate a pool (currently that's ~63.6M ADA). So, there's not a lot of benefit for wallets/users to delegate their stake to a node which is over-saturated since the block rewards will have to be divided among a greater number of people.
However, the stake pool operators have almost no control in the governance/control of the protocol and are only responsible for providing trust/decentralization to the network.
Theoretically, if any single miner controls >51% stake then the security of the blockchain is lost. Practically, though, analysis has determined that with >50% probability a one-block attack can succeed with only 35% control of the network (see page 11). So, centralization is definitely a concern.
Now, if you treat all organizations as "independent stake pool operators" and don't denominate based on corporate structure/private ownership then you'll notice that the largest stake is Binance with 12.36%. I've read the details regarding the provenance regarding that chart, I'm not sure how accurate it is. To be sure, there's some uncertainty in these numbers.
However, my guess is that you'll see this distribution swing over 12-month periods as people seek higher returns from smaller SPOs and move funds to/from different exchanges who compete on rates.