The bitcoin blockchain has placed a 1-megabyte limit on the size of each block, which has limited the pace at which the blockchain has grown. That limit allows simple computers to be able to maintain and run a node. Should the size of each block increase, or should the blockchain be used for more sophisticated processes such as those touted by blockchain enthusiasts, it would become too large to be run on individual computers. Centralizing the network over a few large nodes owned and operated only by large institutions defeats the entire point of decentralization.
