I've said this before and I'll say it again, It's a bad idea to base your video production businesses on iPhones. Let me tell you why.
When businesses need video work done, they expect to see their money's worth. Sure, the image quality on iPhones are good, but if you show up at a business's doorstep trying to sell them on your services and all you use is your iPhone, they're going to say something like, "We already have some contracts with another business and we're happy with them." or, "We'll keep you in mind.". Trust me, they won't give you a second look. If businesses are going to spend money on video production, especially for advertising, they want the best they can get.
Don't get me wrong, independent filmmakers and experienced amateurs do amazing things with the IPhone images, but serious businesses want serious people and most businesses don't see IPhones for video production as a serious business.
Maybe it's a millennial trend or maybe it's actually where the industry is headed. At this moment in time though, it is seen as a joke and most businesses won't want anything to do with a trend.