Drama critic: There were many interesting plays written last year.
Conclusion
None of last year's plays will be popular several centuries from now.
Evidence
The only plays that continue to be performed regularly over many decades and centuries are those that skillfully explore human nature, and none of last year's plays skillfully explore human nature.
Evaluate
It's pretty tough to even diagnose what's intended to be the Conclusion vs. the Evidence. We know the first sentence is a fact. The second sentence makes three predictions (predictions are always opinions), so any of those claims could have been a conclusion, but the author didn't offer any support for why "some will gain popularity" or why "some will receive high critical acclaim".
She pivots with a "but", and usually in arguments, pivots like "but, yet, however" indicate that everything before the pivot was NOT the argument, and everything following it IS the argument.
Her last prediction in that sentence is that . Why should we believe that?
She supports this prediction with the last two claims, which combine a conditional rule about "what will be regularly performed centuries from now" and then a fact about last year's plays that triggers that conditional.
Whenever we read two consecutive claims that chain together or that synthesize into one takeaway, we should pause and perform that step.
The 2nd to last claim is a conditional: continue to be regularly → skillfully examine performed for centuries human nature
~skillfully examine → ~continue to be regularly human nature performed for centuries
And the last claim is a fact (or a conditional, if you want to think of it that way) that triggers that contrapositive: Last year's plays → ~skillfully examine
We can chain those two together, or if you prefer, we can apply that rule we were given to the fact we were told about last year's plays. Either way you slice it, the synthesis is this:
Last year's plays are not going to be performed regularly over many decades and centuries.
How does that compare to the conclusion the author derives? Last year's plays are not going to be popular several centuries from now.
Comparing the inference we get from the final sentence to the inference the author thinks we get, in her conclusion, allows us to see a gap.
Goal
The author is going from If it's not performed regularly over many decades and centuries, then it's not going to be popular several centuries from now.