Not a computer guy...but I think that was the original intent. A little here and a little there. Nobody would notice. All the polls said Biden would win so what did you expect?
The problem for them was that POTUS was cleaning their clocks in an epic and unprecedented way. He got millions more legitimate votes than they EVER anticipated and had to throw the fraud into overdrive. Stealing a couple thousand votes here and there is one thing...but they were forced to produce hundreds of thousands of illegitimate votes. That's impossible to hide...as we're seeing.
not only the volume of numbers but distribution - it’s always been clear they’ve been rigging elections but it was considered to be localized instances + locations; this time they had to go to the extreme in every corner of the country and it eliminates the “isolated incident” outside the norm narratives.