It will not. Person B will inevitably choose a different hobby. Person A is thinking about their costs/legal risks. Person C is running his node not to prevent other people from doing something but to enable themselves to use bitcoin without intermediary. To explain to you like you are 5: Bitcoin does not need you. You don't help Bitcoin by just running a node. If you want to feel special for running a node AND also it to be super easy, you should look into some PoS coin & go back 8 years in time. Running bitcoin node is for people who want to be their own money transmitter (sending and receiving bitcoin) - which is 100x more legally challenging in current world then being jpeg transmitter.