"I have failed to invent a light bulb" Broken implies it was working to begin with, or can be compared to something that works, as the post you're replying to states.
sure, but the thing that's broken was just that, a "thing". It wasn't a "lightbulb", because it was never able to produce light. It's a broken "bulb", at best, and that's a correct use of the word "broken", because it can be compared to other bulbs that aren't broken, in this case the glass bulb itself.
Say you're selling a lightbulb and millions have bought it and then one day the millions of bulbs you've sold to millions of people all explode at the same time.
What?
Say you're trying to invent a lightbulb. The first one ever, and it explodes when you plug it in. How would you describe its state?