I see your thinking here. Lots of people have ideas, or desires, and if they want the same thing they can validate a market. People looking to make things can pick a known market.

Logically it makes sense. Practically though it won't work, there are too many hurdles to overcome.

Firstly, you need a large group of consumers, and a large group of producers. It's hard to build things that need one large group - building 2 is very difficult.

Of course most ideas will be between nonsense and very niche. Because "good" ideas are fewer anyway, but also more obviously marketable. As in that every product ever made exists without your portal, so you'll provide an outlet for every other daft idea. Yes there'll be good in there. But it'll be drowned in noise from the bad.

It's not clear how you fund this sort of thing. You can't charge consumers. And producers can read the site for free. And of course given that it's public if you like an idea, chances are 10 others do to. So plenty of clones.

Companies that make things already have large, effective, market research teams. This sort of "random collection of people" isn't terribly appealing.

Product development is a complex dance. Having a random community "drive" product development, is basically "built my committee ". That never ends well.

In short. I'm not your target market. I don't think you have a target market. I think your product idea has problems... now if only there was a website where you could post ideas and get this sort of feedback ... :)

Keep thinking, and keep asking. You have a good idea in there, and you're smart enough to get some feedback before building. So you're on the right track.