You can write off any part of a storyline with that kind of logic, A had to happen to B because the game needed C - fill in the blanks. The NCR needed to be locked in a stalemate with Caesar's Football team at Hoover Dam because the game needed this drama and tension.
And, yeah, Liberty Prime was there as Hollywood style wow-effect. And you know what? It was [censored] awesome and I loved every bit of it. I loved how "nonsensical and disrespectful" it was to the series (it wasn't). It was this prehistoric behemoth that was built by a government in an age where the Cold-war technically never ended, and culminated into a really, really bad war.
But, please continue to look down on everyone that doesn't agree with your definition of fun (whatever that is - [censored] having fun). https://www.youtube.com/watch?v=XdofmoYcJNE.
P.S. Dornan was a caricature of drill sergeants. https://www.youtube.com/watch?v=6BsQYLkUKy8.
Ignored.