That's not how terminator works, nor is that how modern agriculture works.

Fields for seed are far removed from productive fields. It's trivial to keep them separate from contamination; in fact, it's essential that this is done to make selfs or directed crosses.

Terminator was made to address concerns about transgenes entering the wild. Think of it like a mule; you still have offspring, but they're infertile. That's what terminator does. It cannot ruin a crop. Seed is still made and can be sold and eaten. It simply is infertile.

A construct was first developed by the ARS and USDA, and they were quite right to pursue this. It's a useful technology.