This is actually a very helpful comparison. Much more so than a 14 to 15 comparison, because Apple doesn't really expect users to upgrade each year. I'm sure they would like you to, but it's not realistic to expect it and that's not really who they are selling to.
I do, however, disagree with the article's conclusion that the upgrade is meaningful. I appreciate the honesty of those who have posted in this thread about their experience of doing this exact upgrade.
Now, as I sit here, using my 13 Pro and hovering over the 'buy' button for a 15 Pro, I wonder if after a few days I will even notice the upgrade. The 13 Pro photos are 'good enough' and all the other features will disappear into the background after the burst of dopamine from the purchase fades away.
Ultimately, for the second year in a row, I don't feel excited about the new phone and I suppose that's my answer right there. The new gimmicks aren't exciting to me, so why spend the money...? I just need to stay away from Apple stores for a bit. 🤪