No need to. Why steal the whole cow when one can steal just enough milk as is needed without anyone noticing? As with embezzlers, the best are able to skim for years or decades because they consistently skim enough to do damage but little enough to not out themselves or even raise red flags and usually only get caught when they get greedy, get sloppy, get overly confident or tell someone their secret(s).

Turning just enough key precincts, counties, and states blue while leaving others red (most with RINOS who are basically Dems in Republican clothing) 1) gives them control of those entities and the ability to further their agendas there and 2) gives the illusion of an organic, gradual nationwide turn to blue without raising obvious concerns about it. (Dr. Frank's presentation at Mike Lindell's symposium said that even in states in which President Trump actually won, the results were skewed to make it appear that he had won by smaller margins than the actual margins, thereby attempting to make the steal more believable by pushing the illusion that he was less popular [and Joe was more popular] in those states he won and setting the stage for greater Dem "popularity" in those areas in the next election.)

Elections have always been compromisable. Even with manual counts, votes can be "miscounted" on purpose by the counters, votes can be bought, ballot boxes stuffed and voters kept from polling places (through intimidation, bogus requirements like needing to know how to read, etc.), so probably no one knows how long and how purvasively they've been rigged to flip local, state, legislative and Presidential elections. According to Jovan Pulitzer, though, elections utilizing computers have been compromised since at least 1970. ( Source: https://www.spreaker.com/user/jovanhuttonpulitzer/swapped-votes-dropped-votes-phantom-vote ) So, the slow drain, right under everyone's eyes, has worked for a long time.