First, they understood the principle of inertia...that a body at rest will stay at rest, and a body in motion will stay in motion (for at least some time frame)
They knew that, if they got enough political inertia, that in the short time frame, their illegal and anti-American tactics, no matter how flagrant (illegal and forged ballots, interference in the electoral process, ballot harvesting, illegal voter drives by government entities that were focused on getting out Democrat voting or other actions) would simply be paved over by political inertia.
They KNEW that if they got the media to begin proclaiming that the election was over and simply stalled and obfuscated, that deadlines would pass and no matter what happened later, the election would not be reversed.
They had to get past Voting Day (in this case, "Voting Months". Then they had to get past the Certification of Results. Then they had to get past the Electoral College...Swearing in of Congress, and Inauguration Day.
With each milestone they passed the power of the political inertia became greater and greater.
So they stalled. They stalled at every single point. They ensured that no court would pick up any cases, and those that did, they threw out on flimsy legal grounds such as "no standing". They lied, bought people off, publicly denounced people and politicians who protested, and then in cooperation and collaboration with the Government, Media, and Big Tech, did everything to make everyone asking questions up to (and especially President Trump and any member of his cabinet or party) an "unperson".
Astonishing.
It worked.
Done fully in concert with elements inside and outside the country to elect a candidate beholden to our greatest enemy, a President and Vice President who want to destroy this country and in the short time they have been in office, have been succeeding wildly. And they knew that even if it all came to light...it would be "old news", in the past, conspiracy theories, and no action would be taken.
They knew they would get away with the loot.
If only for this one election cycle, they knew it.