When I buy/sell bitcoin on Coinbase, am I considered part of network? Yes the transaction will be part of the blockchain but I am not participating directly rat

When I buy/sell bitcoin on Coinbase, am I considered part of network? Yes the transaction will be part of the blockchain but I am not participating directly rather using proxy (in this case, coinbase for it). This is what I meant by powerbroker. Second, to my scaling point, In order to be a part of a network one has to maintain a complete blockchain on local server/computer. This is something just not scalable in practice for 99% of people or the use-case... so regardless of the intent there will be an emergence of powerbrokers.... So using the internet analogy, yes internet is decentralized but who owns the backbone (att and few major players) will be the case for blockchain.