the distribution of coins is still better on Steem than Bitcoin

What do you mean exactly by distribution? people who are using the coin, people who are mining or getting or using the coin? those are different chains, and the consensus for transaction refusal is not reached in the same way even if the technicality of it (transaction refusal) is the same.

`considering that the trend is for ever increasing concentration of coins into fewer and fewer hands and the same for hash power``

Unless those people are using nuclear fusion and not seeling anything to cover the energy cost.

You are mixing Bitcoin (the coin) with the question of hash power and transaction refusal consensus.

people can cooperate to ignore transactions without any problems what so ever

A known fact.