Often when you're creating something like this, you don't know if it will be the final selection. Some people can't visualise, so the designer may end up creating something without knowing it will ultimately become the final product. Given that they might make a number of attempts, it's very easy to throw in an image thinking it's temporary and forget about it in hitting deadlines and getting a project over the line.
Then unless there was a meticulous review process, I can see how someone might overlook a very default, straight on view of a generic product.
I haven't thought of this, but I indeed saw something like this happen.
Quick mockup of how it could look like, but because the client saw this first and said "this is the one I want", they actually like the mockup better than the final version with similar but not quite the same graphics.
Yep, happens all the time. Or you say "I've used a placeholder image. Can you please select and buy a stock photo that you like?" And they never do, and it all gets forgotten.
Then unless there was a meticulous review process, I can see how someone might overlook a very default, straight on view of a generic product.