Btw, I don't think it's "hybrid plants", more cloned plants that don't have seeds (but I'm no farmer!)
If you take a heirloom plant and take the seeds from it at the end of the season and dry them. You can plant them in the spring and you will again get whatever plant that was, tomato, beans, rutabagas whatever. If however you do this with a hybrid, you get nothing, like a mule, it can’t reproduce. Once the plant is gone that plant is not ever coming back. Also, if you plant hybrids with heirlooms they will cross pollinate and again after a season you will get a none reproducing plant. This is not a good thing. Also, you have to replace the seeds with hybrids year after year. However if you have a heirloom plant, you can get the seeds and replant year after year for decades.