Petunias are perennials. They are not annuals. They are often grown as annuals because they are native to the subtropics and frost sensitive. You can grow them for several years as either a houseplant or outdoors if you can provide the climate conditions that the plants need.

I know there are laws about importing foreign plants which might set seed and grow locally, becoming invasive. A modified plant that had any chance of establishing itself would probably face similar obstacles. I believe roundup-ready corn was sterile and, of course, an annual.

It's only annual if you plant it outside.

lol. There exist bioluminescent aquarium fish that live for several years. Clearly the market will provide the plant the customer wants.