The real question is why anyone would not.
Before you reply remember random mutation is common - normal in nature. what is the difference between a random mutation and one a scientist comes up with. So far the only one I've found is random mutation isn't studied for safety.
From my perspective, this is a slightly naive opinion. I believe we're not fighting against GMOs because "mutations are bad". When activists point that out, it's because it's the easiest way to reach the general population and convince them to get behind the cause.
The real reason, however, are the political and economical implications of GMOs. Sure, they say they'll use them to fight famine. But in reality, they'll just try to extract as much profit as they can, regardless of the interests of the people growing the plants and eating the food. We've seen farmers get sued (see Bowman v Monsanto) and other evil stuff like that.
Also I appreciate many of the random human interactions I've had with Uber/Lyft drivers. Of course not every ride was great, but many drivers had stories and experiences that no one I usually meet would have. For me, the safe but bland experience of a self-drivng car isn't worth losing the human touch, not to mention taking away income for human drivers.
So far the answer of the current economic system has been to invent new products/services and redirect the workforce there. It's been working so far, but isn't without issues - ever-increasing consumption is bad for the environment; the jobs are getting more and more pointless; people wonder why automation doesn't result in shorter working hours for everyone.