I should advise that its not 20-30 years at currentlevels
Solar PV degrades at around 1%/year. At 80% by year 20. The question will be "why bother replacing?"
Will the uplift of 20% be worth the trouble. The short answer will be no.
What will happen is farmers axe. move panels around until you can have a complete electrical section vacant and them populate with new ones rather than a hodge podge of differently performing devices on the same circuit., and just let the remainer continue to die.
No robots or fancy stuff.
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