When a pre-launch landing page works

Recently I had a thought about when a 'coming soon' landing page (with a mailing list subscription) can work.

In a crowded market, when the product is just one of many, with no obvious 10x improvement over the others, it will be quite difficult. The reasoning is that people might see the landing page and think to themselves that it looks good, but they have it already with that other product. Without the ability to try it out, they cannot feel the difference, and therefore have no reason to subscribe to the newsletter.

If the product enters a new market, people cannot use an existing product, because there is none (they know about). So it solves a problem they currently have no solution to, and therefore a strong incentive to know when the product is released.

Note that I'm talking about conversion rates here. My thinking basically comes down to this: If a person that has a problem the product solves, and they have no solution for it right now, they have a strong incentive to sign up. If they already have a (bad) solution, that problem is already (kind of) solved for them.

What do you think about that?