That would be true if the batches represented random samples of ballots from the total set but they do not. As far as I can tell the batches of ballots are associated with particular vote centers or ballot collection points. As a result they represent the votes of a particular area or set of voters and therefore will not have the same distribution of votes as batches of ballots from other areas.
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.