I will be really interested to see what informed responses this gets.
In no particular order - OP, FWIW, the NICE guidelines actually say that for a first time mother, birth within 3 hours of the 'pushing' stage is to be expected, and that a diagnosis of 'delay' should be made after 2 hours, and after that an HCP brought in who can attempt an operative delivery. So.... you could argue that there WERE signs something wasn't right with your friend's birth, but no one acted promptly.
welcome to the world of NICE guidelines, btw. They exist but no one actually has to follow them.
Re: labouring for 3 days - I don't know long nulliparous women usually labour for, but while there are women who would rather head to theatre than go through a long labour, there are also women who fear being 'rushed' into intervention and would rather be allowed to labour this long. You can have a very slow and exhausting labour without anything being wrong as such.
Anyway - as to learning signs that things aren't going well that you could spot yourself.... that's a tricky one. tbh, it's only something like a baby's heartrate dropping, or blood tests from a fetal scalp sample that says something is badly wrong. CS's do happen because of maternal exhaustion, but I don't know how far the mother gets to make the call on that. Then there's 'failure to progress' (labour stalling) which presumably didn't happen to your friend, as she got to the pushng stage, so she must have been fully dilated?
MWs are supposed to be able to guess a baby's positioning to some degree - but there are plenty of stories here where MWs had no idea a baby was back to back (or if they knew, it didn't change their approach anyway...) - short of a scan, they don't really know for sure, and you don't get scanned during labour.
Being blunt, severe pain and stalled labour could be sign something isn't right - but then these can be features of a 'normal' birth. As a first time mother, you have nothing to compare it to anyway. (which I think is a reason some first time mothers are not listened to enough during labour, as per elizaregina's post).
Re: epidurals - well, yeah. If you are not put off by horror stories, read the thread asking who could have coped if they hadn't had an epidural. It is very misleading for any HCP to give the impression you just have to ask for one, and it will appear.
I will be very interested to see what responses this gets, anyway.