> Also, as a student, I didn't have the money for a patent application.

That's the big probem for individuals.

Patenting as an individual is expensive and as a friend learned the big companies can just sit-tight until the renewal fees become too much to bear.

He had designed a self-assembly glassfibre astronomical observatory on the Buckmeister principle, with a wide-opening orifice using petal segments, and toured the major manufacturers in the field. None wanted to license the patent.

Shortly after he let the patent lapse due to cost, several of the manufacturers brought out their variants. That's just the way the game is played.