Solar panels are cheap these days; wouldn’t be terribly surprised if they take the data center approach (if a few machines die, well, who cares, deal with it next time a major overhaul is required).
I would expect a middle ground. They collect statistics from the inverters and when one doesn't report, or reports lower than expected levels they schedule maintenance for next time somebody is there anyway. But yeah, they probably replace a whole string of panels at once. I expect someone will design a crane for this purpose so the whole string can be done quickly - most of the work is at ground level.
I'd also expect that they have a crew to wash them off once in a while (I'm guessing yearly), but this is cheap labor not electricians.
