Many will not like or agree with the following and that is acceptable, if, you can offer a valid counter argument.
"Decentralization has two levels: block production and team (governance).
Decentralization is based on holding a scarce resource. In the case of Cardano, it is the ADA coin, in the case of Bitcoin, it is the hash rate. Many people believe that decentralization can be measured by the number of nodes in a distributed network. This is a misconception, as decentralization requires protection against Sybil attacks. A single entity can run thousands of nodes almost for free.
There are over 3,200 pools registered in the Cardano network. Blocks are produced by about half of them. The 5 largest block producers have shares of 8%, 4%, 3%, and 2%. Similar to Bitcoin, Cardano uses the concept of delegation. In the Bitcoin network, miners delegate hash rates to pools. In the Cardano network, stakers delegate ADA coins. There are around 1.3M stakers in the Cardano network. Hundreds of them would have to join together to have more than 50% of the ADA coins.
In the Bitcoin network, the Foundry USA pool produces around 32% of the blocks, and AntPool 21%. The other 3 pools have shares of 18%, 8%, and 6%. If the two dominant pools cooperate, they have more than 50% control over the hash rate. As for the miners, these are the entrepreneurs today having tens of thousands of ASIC miners. It is estimated that the 50 or so largest miners collectively control over half of the hash rate.
Every blockchain project has a team, a GitHub repository maintainer, and someone who signs off on new client releases. Every software project must have someone who manages the project and approves changes. There is no other way.
Cardano is transparent and has 3 founding entities. The roles of IOG and Cardano Foundation are important. IOG is involved in the development of the protocol.
When Satoshi Nakamoto left Bitcoin, he handed over management to Gavin Andersen. He subsequently founded the Bitcoin Foundation. It is not true that Bitcoin does not have a formal leader. Project management is being handed over, the process is just not transparent.
The last 10 BIPs have come from 2 developers, Andrew Chow and Pieter Wuile. Both of these developers work for the VC-backed company Blockstream. The CEO of Blockstream is Adam Back. There are multiple VC-backed companies in the Bitcoin ecosystem that are involved in funding Bitcoin development. All of these companies have a CEO.
IOG is working to establish on-chain governance. The first steps have been taken. ADA holders vote on the distribution of $ADA coins from the treasury to fund projects in Catalyst. Meetings are being held around the world regarding CIP-1694. Entering the Voltaire era has been on Cardano's roadmap since the beginning of the project.
Summary: In terms of block production, #Cardano is orders of magnitude more decentralized than Bitcoin. In the case of governance, the projects are very similar. Cardano is more transparent and is moving towards on-chain governance. In the case of Bitcoin, there is censorship in the main communication networks. The governance process is less transparent."