No, it wasn't that. There used to be (maybe still is, I didn't check) a core group of reliable servers. I remember having a client idling on them for weeks without reconnections.

What was missing, I think, was lack of client development and adoption. There was default CLI client which was a weird fork of Irssi, then there was plugin for Irssi, and not much else.

There were of course few small client projects, but few of them got past early alpha stage.