We really don't know, anything could be possible.
I think 'The Fame + The Fame Monster' would have sold somewhere at 25-30 million copies.
And ''Born This Way'' somewhere at 10-15 million copies.
But I really don't know, without the digital era, we wouldn't have twitter, facebook, youtube and that massive promo that the internet is so not that many people would have known about her because she is so big in the online world and I couldn't imagine her without all the online press, music videos, criticism and all thing that happend online and get people interested in her and makes them buy her music.