Gleba is also the most complicated and difficult planet in terms of spoilable products, so why shouldn't it have the biggest reward?

Sure, you will start getting an infinite supply of legendary materials, but that is the point, the player has worked their way all the way through the tech tree ...

This one is fairly self explanatory, legendary quality seeds should create legendary quality trees, which produce legendary quality jellynuts and legendary quality yamako.

Same for the other quality tiers.