There is only one cast-iron guaranteed way not to run out of ideas, and that is not to have any in the first place. However, short of being born pre-lobotomised this is not really a feasible approach, and so those parts of humanity which like to worry about such things has not had any need to worry about lacking a need to worry. And those people who enjoy worrying about a lack of ideas the most are those in the so-called creative industries, and those facing immediate death.
Now you may say that writer’s block is not as serious as having come to a blank as the water level exceeds the height of your nostrils, but on careful reflection you will note that only the former is going to be a genuine long-term problem. A painter without a muse is pretty much bereft (although the scent of money is sufficient muse for all but the most pure of purists) of all purpose in life. A man who has failed to distract the firing squad is just bereft of life.
This of course leads us to that most thorny of problems: if a writer with writer’s block can just write about writer’s block, is writer’s block really a block? And why isn’t writer’s block the most written upon subject? Is it because the sufferers lack even the most basic of ideas, or is it because procrastination is the real diagnosis?
In truth, I have no idea.
Severely odd 
Whenever I get writer’s block, I just decide to write the crappiest thing I can think of, one that’d have critics reeling in their armchairs. That usually frees me up enough to start writing.
Also, a career in journalism with one-day deadlines has done away with many a writer’s block. Great post. Thanks for sharing!