Its a bit of a well kept secret. It does not represent maliciousness on the part of Ethereum or centralized node providers - its a consequence of the network doing nothing to compensate for nodes to deliver data to-and-fro. Miners and businesses stand to lose if the whole network crumbles, so the bare minimum is done to supply nodes, which means centralized node hosting.

A fully scalable, sustainable and decentralized network compensates all infrastructure important to the network, which means mining (consensus) and transaction/data routing. A nice side effect of rewarding data transmission is that you incentivize speed, so scalability can happen naturally with no conflicts of interest between miners and users.