Quoted from ForceFlow:
Merchandising was a pretty new concept back then. That's why when Fox funded the movie, they weren't interested in merchandising and instead went for the distribution rights of the movie.
Today, merchandising is a huge piece of the pie.
No one wanted to put out stuff for the movie.. toy companies all turned them down. Kenner took the deal, but was so late in the process that toys weren't ready for launch.
Lucas was the prophet in the mix.. but had to give away sweatheart deals to get anyone to trust the concept before the movie actually hit.