"the accumulation of capital by some to the exclusion of others"

This allows decentralised decision making for large grained resource allocation - for example should we build a factory for shoes, or for toothbrushes? - and is a good thing, as central planning has been demonstrated to not work if applied to the whole economy. (the converse, no central planning to any of the economy, has also been demonstrated to not work!)

However that accumulation can be (and nowadays usually is) orchestrated by a corporate entity, which in an ideal world would be almost entirely beneficially owned by retirees on an equitable basis.

What has gone wrong, is that the benefits of productivity enhancements (since 1970?) have flowed to capital more so than to workers - which not least prevents them from forming capital themselves (savings/pensions), hence rising wealth inequality.

Maybe, and you really believe that, then you do believe in capitalism as Louis Blanc defined it, even though he invented it as a way to characterize something which he regarded as bad.

But this kind of thing, i.e. capital accumulation by some to the exclusion of others, is, I think, objectively problematic in that it's not really compatible with free markets since capital ownership will be barrier to entry once capital has in fact been accumulated by some to the exclusion of others.

I agree that it is decentralized though, but sort of like how feudalism is decentralized.