As long as we have a patent system, patenting plants (especially with the heavy restrictions on plant patent eligibility) is a reasonable extension. Since the origin of agriculture, you've had the "right" to copy your neighbor's cool new invention to till the soil better without issues. As a society, we decided that giving inventors patent rights for a limited amount of time is going to encourage innovation and investment into new technology. The founders thought it was important enough that we embed it in our constitution, and since the founding of this country, patents have been a driving force in industry. Maybe there's a better way to support innovation and make investment into r&d happen. I personally don't find the alternative arrangements people have tried so far all that compelling- but im open to the idea that this isn't the best way to do things. For now though, I think I'm getting a good deal out of a patent system where the creator of the cotton candy grape is able to spend 12 years developing a cool new variety because they'll get a return on their investment over the 20 years following their product's launch. Patents paid for a lot of the products I use day to day, and unlike copyright, patents actually expire after a reasonable amount of time.