Do you have a source on expected productive lifetime of solar panels, or are you just expressing your "feelings"?
Pretty sly tactic to give a moving target like "incremental gains" in a decade. A lot like a Tarot Card reader or someone who adheres to the predictions of Nostradamus. Keep it vague enough and you can always say you were partly right. If you would be kind enough to define what an incremental gain is, we can go from there . . .
I agree that physics and chemistry are real. Feelings, not so much.