Question about SegWit

Hello everyone!
I’ve seen some similar topics but i think my question is somehow a bit different still…

Oh, and please let me know if i’m in the wrong section!

I’m curious about one thing :

We said that SegWit was a soft fork right? The rules and the code had been changed but with no implementations, it was only a contraction. So far so good .
Nonetheless a soft fork, in the end, is not supposed to split the chain which means that at some point the network should recognise which of the 2 coexisting chains is doing more PoW and refuse the other one. So how is this possible? Segwit has changed the transaction system completely and also allowed the support of second layer protocols! In my head i see that this created 2 very different variations of the same thing but if this is not a hard fork it means that at some point the network will have to refuse either the transaction system that was there before SegWit, or SegWit transaction system itself. How come they coexist without being on 2 different paths? I really don’t understand this!

If anybody can help please let me know :slight_smile:

Thanks very much, i hope my question makes sense!