Here is a post that explains the witness pay. The ‘miner’ was replaced with an additional top witness (there are 20 now instead of 19) but the calculations are all still correct.
https://steemit.com/witness-category/@timcliff/til-how-much-witnesses-and-miners-make-per-block

Affording servers is not an issue for the top witnesses (assuming the price of STEEM stays above a certain level). The costs are a lot harder for the backup witnesses though - many of whom run their servers at a loss. There are also exchanges that run nodes, and if the costs for those get too high - we risk getting delisted from exchanges. Many third party developers also need to run nodes to support their applications - so expensive nodes are bad for them as well.

It is important for us to keep the costs to run servers in mind - because a lot of important parts of our ecosystem depend on running servers. Right now the cost per legitimate user for running the network is on the high side , and spam is part of why that is. That’s basically where the post is coming from, even though the particular solution being proposed doesn’t sound like it will fly.