It's the notion that seeing reality helps a lot. Once you know what is there, you can have ideas that can help. Whereas ideas that are not based on reality are very unlikely to work.
minor e.g. I find that my problem solving works best once I've started trying something. With each thing I try, I notice more: similarities, patterns, gaps that could be filled, things that could be connected; and I have ideas about how other things at hand could be used to do that. These are often obvious in hindsight; but I didn't think of them at all beforehand.
Of course, one might not succeed anyway - the pop. stat. is 9/10 businesses fail. But not discovering reality has even worse odds.
Every success that started with a lousy idea became a success because they recognized their idea sucks and changed it, not kept perpetuating failure. It is a very dangerous attitude to just dismiss legitimate feedback, hope everything just magically fixes itself and lull yourself in the sense of complacency that "it will just work out". Hope is not a strategy.
Of course it is inspirational to know that even if you start with a lousy idea you could be able fix it. But don't assume the solution will just fall in your lap and do the hard work pivoting your product and business.
So I guess I still agree you shouldn't sit pontificating on business ideas, but you shouldn't just dive into building a complete something either. There is a rich middle ground.
For a while I was fascinated and amazed at projects pursuing absurd mega-goals, attempts to get something off the ground so big it was nigh unto stupid. A floating city configuring an independent libertarian utopia nation. A billion-dollar indoor ski resort just outside Atlanta. A bridge from Spain to Africa sporting a 5 mile suspended span. A world-class [fill in the blank, how much ya got?] facility annex to a super-mall in "why would anyone move there" Syracuse NY. And so on, one project after another with big flashing "ain't gonna happen" signs over them.
Then I realized. It wasn't success of the project that was the goal, it was keeping a small team of creatives employed in a perpetual state of promotion and study-funding: find someone with deep enough pockets, and they'll shell out a livable fee to be able to say "hey, look at this..." to other deep pockets. No way that Atlanta ski resort would happen, but the idea was exciting enough to elicit enough funding for studies to pay the bills (at least until the vital-to-snow-making nearby lake almost dried up) for a few people in modest offices. You can make a nice living promoting stupid ideas.
And if the stupid idea actually pans out, takes off, and succeeds, well, the possibility of success is awesome enough to keep trying.
The Atlanta ski resort was planned to be 4 times bigger than the Dubai one, and it hits 100 in the summer here too.
joke about your idea and test it, and you will suceed more likely could be the message here
My idea... well it doesn't suck, but it was more work than what it needed to be. After a few thousand customers I realized what needed to be done. Now it's better but not quite where I want it to be, still need to pour more $$$ in to get it there.
Problem is you need at least a few hundred customers before you start noticing the cracks in your idea. If your idea sucks so bad that you can't get a few hundred people to believe in you enough to give you $$$ then it probably is so bad that you shouldn't do it.
(no, i haven't submitted to ycombinator yet, I'm waiting for a swift kick in the ass)