From a distance in time it is hard to see many historic photographers had a defined style - because over the years so many others have sought to emulate them. I'm sure at the time they had a readily discernible style. Rob C says he could easily recognise a Bailey in the 60's - and I believe him.
I usually recognise his B+W work when he does the odd magazine job, even though he's before my time.
And yes, certain styles came about at various points in history too, because as soon as something new comes along it is copied. I completely disagree with RSL that you cannot discern style in outdoor photography. I know lots of local photographers and I can easily tell their work apart when I see it. Not every time, but most of the time.
And some people say "all ****** music sounds the same to me"
and insist that it is not them that cannot distinguish between various distinctly different artists, but a failing of the music [that they do not like].
I asked who the photographer was and was told "you wont know him, he's from miles away and we got married over ten years ago". Well it turns out that I did know the photographer and had been working with him as a second shooter a couple of years before the pictures on display were taken. In addition, they looked a lot like my pictures, which illustrates that my 'style' was heavily influenced by the photographer when I was starting out
I often wonder if it is always influence as such when seeing someone else's work or that's what you like and would tend to do anyway. Maybe you were employed as second shooter because
your styles were compatible/similar in some way and your work may even have had influence the other way.