That's a point to consider, but one that bears further scrutiny. Which collection points? Why were they held back until the last count? It's not like California or New York even - these are close battleground states where the population overall is pretty much 50-50 (or, 33-35-30). Which section of town leans 2:1 Democrat?
All that aside, I agree with some other pundits that changing the laws is an uphill battle - and so it is high time that Republicans change the ground game. Get into more events, more ballot harvesting etc. Maybe just maybe if the Democrats lose the way they have won (assuming that these are nearly all legitimate votes and not U-Haul vans pulling into the dock at 3 am or voting machines hacked by poll workers) then they will come to agree that the system needs to be corrected.
It's nuts that it takes them a week to count a couple 100,000 of the last ballots (when they can count the first 2 million in a day), and that those ballots end up being the decisive ones by the exact margin needed to win.
I am not from Arizona so I don't know the voting characteristics of the people who go to their voting centers. From what I understand their voting centers are not tied to the home address of the voter, so each voter can choose to vote at a voting center that is convenient to them, or vote by mail.
Here in New Hampshire it is not uncommon to see towns or wards within cities that have 2:1 ratios between the parties. The averages for the whole state may show close races but the results from individual towns or wards are often heavily skewed to one party or the other.
Many urban neighborhoods vote 80% or more Democrat, and some rural areas vote more than 70% Republican in places like Pennsylvania.