Sure. By centralisation here I'm referring to the gradual reduction in the number of block-generating entities. To be clear, I claim: absent a block-size limit, this centralisation process would occur naturally and that a good relay bandwidth market would accelerate this process.
Always happy to be proven wrong; just want to give you something more concrete to work with.
The number of individuals who control hashing equipment has been increasing since 2008, during the time in which the block size limit is effectively non-existent (because tx volume is too low to be affected by the limit).
Why are you predicting that this trend would reverse instead of continue?