Take up pottery and every mug in the house changes. You start turning them over, checking the foot, noticing where the handle joins. The mugs were always like that. Your attention was elsewhere.
Ideas work on the same principle. They do not arrive in a person who has nothing to catch them on. The supply is genuinely enormous; what varies between people is how much of it they are equipped to see.
Which is an argument for the unglamorous part — learning a craft badly, for months, so that when something interesting drifts past you recognise it as material rather than scenery.