I don't think this is the majority opinion at all. Libraries and NC in your capital give you less science in the first 80 turns than extra cities and a caravan.
If his one city national college is induced by Great Library [which would result in one city national college before turn 55 and his second and third cities built by turn 80], it's a good one; except that when he moves up a difficulty level he'll have difficulty beating the AI to it.
Without the Great Library it would take a start with terrible gold & hammers for a two city NC to be significantly slower than one city; and I'd notice that in 4000 BC and re-roll.
In my games, up to Emperor level, it is better to get NC with capital only due to the usual poor starts for Russia. If you happen to get a really good start with some extra luxes around (different than capital area and far enough away from capital influence) then sure, go for multiple cities. Otherwise, it's not worth the penalty. This is actual play, of course, where the AI winds up teching far faster than I do if I have multiple cities before NC (Tradition, not Liberty, which the latter would mean multiple, of course). YMMV, but this is my experience from vanilla through BNW with a couple thousand hours of play using only Russia.
I do not reroll to get a decent start. I may quit a game by Industrial because it gets boring or goes against my preferred playstyle at the time, but I won't simply reroll in Ancient or Classical to get a better start.
And no, I do not try to get GL. No point.
Example: current game, isolated middle of continent on Continents, three city states but only one in caravan reach (for 5 gpt trade route initially, wee). AI techs ahead while I get NC but then I outtech them easily, at least for the next era or two (up to Industrial, sometimes Modern). Lousy luxes throughout continent.