If bitcoin becomes fully fledged monetary system things like enthusiasm, altruism, philanthropy and philosophy will not be enough to secure its future! After all, it is about money! All tricks will be used both technically and economically to game the system and abuse it. Every expense that is possible to avoid paying will not be paid by participating agents in the network! There is no doubt about that... The big question here is whether all those avoidable expenses are fundamental incentives to keep bicoin network running?
maybe i should frame it differently. i also have an economic incentive to leave my computers on to support the network. i have a substantial investment in Bitcoin as do many others who compose the network. its about taking care of one's money. you don't just leave it out on the front lawn for anyone to take. you build a safe in a remote area of your house and fortify it to the extent you feel comfortable. you may buy a few guns also just in case. it may cost me a few cents to keep those computers on but i want to take care of my money!