I think you are underestimating the power and need for promotion. You really think all these companies keep up with what every small company is doing? There are like hundreds if not thousands of small companies that claim one breakthrough or another. And don't underestimate the retail investor that has never heard of Opel. Sure a few retail investors don't make a difference, but a few thousand(s) can make a BIG difference in stockprice. And most retail investors get influenced by promotion. If there is hardly any promotion you won't see them investing in a company they haven't heard off. I only came across OPL due to sevenodouble who is active on a stockforum in my country.
Opel hasn't done any promotion whatsover, I really believe it's one of the major if not THE major reason the stockprice is so low. Milestones are important, but if you don't promote your milestone achievement you wont get a very enthusiastic response. The latest milestone should have made a big difference, but because of the lack of promotion it didn't create the firework we were all waiting for.
If you are a seasoned investor you should know there are MANY MANY small (startup) companies that use a lot of promotion and have a high stockprice even though they have nothing to show for or back up.