1) That's not a reverse merge; that would be a merger. But in any case, it's not going to happen. The other companies are private companies held by the Marley family; they wouldn't give that up.
2) If they merge, there would be no "subsidiaries". That's not what a merger is.
3) A company that does the level of sales that JAMN does and has the assets that they do can't afford to buy out the other companies from the Marley family. They can't just make a bunch of shares to create value. A company that's valued at $40 million with 100 million shares is still going to be worth $40 million if they suddenly have 300 million shares; each share is just worth less.
4) A "combined" company might have annual sales of $85 million, but JAMN is only on schedule for $8 million of that - so the JAMN "share" of that is still only $8 million.