This is me surmising here, but I think that lung capacity may be tied to natural strength of voice. I was gifted with a very strong and loud voice. Did nothing to make it so, I just came that way from the factory. My lung capacity is huge. Again, did nothing to work it up, I just was made that way. But, I notice that, as I am not working as hard to make myself heard, I use less air to support my voice than do those who have naturally quieter voices. It takes longer for my voice to become strained as well.

I would think that getting a vocal coach and learning breath support techniques may help some, but as others have said many times in this forum, that alone will not make you an Opera singer. A lot of it is simply what gifts you were born with.