Am I making a huge mistake?

Just ripped up carpet in the living room & dining rooms. We were told that there was not hardwood under the carpet so we already bought beautiful new hickory hardwood.

Well obviously there is hardwood under the carpet, probably original from 1945. There’s been a lot of movement in the boards, lots of gaps of varying sizes all over. Definitely worse in the middle of the rooms than the edges.

Would I be making a mistake to not refinish the existing floor? I already have replacement hardwood in the house ready to go…