The market segment for cameras declining doesn’t suggest, or prove, that iPhone cameras are better. It’s a reflection that they are good enough for most people when the convenience is factored in. There is nothing wrong with that.
Every paragraph you type contradicts the last. So all these people that are only used to seeing iPhone pictures, because they aren’t willing to buy a better dedicated camera, get fooled by your iPhone pictures when you lie to them by suggesting they were taken with a DSLR. How surprising! People with no experience with high level photography are fooled by an iPhone picture.
The same thing happened in the music industry. Compressed MP3’s were forced upon the world based on convenience, and file size. Now, 20 years later, more and more people are realizing their old records and CD’s sound so much better, due to them containing more information, so now we have lossless hi-res finally becoming prominent.
There is nothing wrong with using your iPhone camera, nor upgrading your phone, but when you upgrade every year simply because you think you need a slightly better convenience based camera, think twice.