could be better

[keannu]

In this writing, don't both "could be better " and "could be worse" have to be correct to "could have been better " and "could have been worse" as the two indicate counterfactual past? Why did the writer say "could be better/worse"? To indicate a general imaginary situation? But it's related to the past.
Can you tell if this was written by a native speaker or a non-native speaker?

ex)Researchers watched many Olympic medal ceremonies. They studied the feelings of medalists. Not surprisingly, the gold medalists always showed the most joy. Then who do you think felt the second happiest? You will probably guess the silver medalists because the silver medal is the second highest prize. But the study showed different results. Strangely, the bronze medalists felt happier than the silver medalists! Why?
Silver medalists think, "I failed. I missed the gold!" They compare themselves to gold medalists and think that things could be better. That makes them unhappy. However, bronze medalists think, "I did well. At least I won a prize." They compare themselves to non-medalists and think that things could be worse. That makes them unhappy. What can we learn from this? Clearly, our happines depends on how we view our situation.

[5jj]

I see no reason to doubt that this was written by a native speaker. The imagined thoughts of the medallists are about the present -"Things could be better - I could be standing where the gold medallist is standing"; "Things could be worse -I could have no medal at all".

[keannu]

I see no reason to doubt that this was written by a native speaker. The imagined thoughts of the medallists are about the present -"Things could be better - I could be standing where the gold medallist is standing"; "Things could be worse -I could have no medal at all".

Okay, you made it clear, thanks a lot! It was the Korean translator who made a mistake as the translation goes "Things could have gone better/worse in the past".