A good question, is there any BTC clone that pay's you to run a full-node out there??
And who will pay for that? Are you suggesting to increase transaction fees even more?
People could spam the network with fake nodes trying to make more money out of it. Bitcoin economy is doing fine
Something has to be done, to have a low-energy cpu based mining strategy, that is equitable to everyone, then fee's are low, and consensus is real, today nobody talks about CHINA controlling consensus its a taboo topic.
There is no technology for that. ASIC are as energy efficient as possible, and if someone makes a more efficient GPU/ASIC it will burn the same power as before because miners will just buy more of them to make more money out of it.
There is no way to have a low cost mining available for everyone. If you want to mine you have to pay for it. This is what makes bitcoin safe, this is what proof of work is about.
If mining is equitable for everyone, so it is for big players to attack the network. Which can't happen.