Great thinking. Just want to memo this here:

https://bitcoinism.liberty.me/2015/01/21/economic-fallacies-and-the-block-size-limit-part-1-scarcity/

https://bitcoinism.liberty.me/2015/02/09/economic-fallacies-and-the-block-size-limit-part-2-price-discovery/

https://bitcoinj.github.io/working-with-micropayments

tl;dr Non-mining nodes can in principle receive compensation for transaction handling without radical changes to Bitcoin.