Comparing an iPhone 6 to iPhone 13 is a worthless comparison. So no, I won't be grabbing an iPhone 6 (which I don't even own, and haven't for more than 7 years) to compare. It doesn't actually matter what an iPhone 6 did. iPhone 13 and 13 Pro are vastly different phones with vastly different camera systems. And no, I'm not speaking of getting to the pore level in photography. I'm talking about close up photos, which an iPhone 13 is incapable of taking.
The simple fact is iPhone 13 can NOT focus as closely as iPhone 13 Pro. It wasn't designed to do so. Only iPhone 13 Pro phones were designed and actually possess an extra camera to take close up photography. Now, there is a workaround to this. And that is to take your phone as close to the subject as you can get in focus, take the photo, then edit the photo to crop in closer and you can get closer to what an iPhone 13 Pro is capable of doing. It is using digital zoom at that point, but is pretty effective.
If you're not happy about that, let Apple know. But don't have any expectation they will be adding Macro capabilities to a phone which wasn't designed to have it. And if you needed a camera system on your iPhone which can take close up photography, you should have spent the extra money for the 13 Pro or 13 Pro Max.
Feedback to Apple goes here --> https://www.apple.com/feedback/iphone/