[Fnoord]

It started out as a necessity, and it isn't new. Its because of netsplits, DoS, and channel takeovers that bots existed on EFnet and IRCnet. Chanserv/Nickserv/X/W (and UnderNet/DALnet) came later on.

> I wonder if the ability to have IRCs running all the time actually harmed IRC since at the past (90s mainly and perhaps very early 2000s) if someone was in a channel, they'd be up for chatting too whereas now channels are full of "zombies".

Untrue; bots existed in past. Take a look at Eggdrop's age, for example. Whether it is much more common nowadays I don't know, but BNCs are nothing new either. If anything, it is because running a computer 24/7 is much more cheaper nowadays (although back then you could get a shell for e.g. 5-10 USD / month).

[Crinus]

Well it isn't just nowadays, as i said it was like that from the early 2000s - at least in my experience. But then it might just be coincidence with the IRC becoming less popular in general.