This is not true at all.
The last SimCity was terrible in a lot of ways (online requirements, small areas, bugs, etc) but it had the best simulation out there: an one 1:1 car / population that made city and road planning a true joy for the nerdiest players like me. Literally every aspect of city planning had an impact on that simulation, and you could follow every car and knonw it was there for a reason. This means that if you have a really bad traffic state every aspect of your city goes on fire.
On the other hand Cities skyline has a lot of other cool factors but traffic simulation comes really short. It is just derived from statistics of the city but there is no 1:1 link to be found, so you can just guess what aspects of the city has some coefficient on the traffic algorithm, and the worst part is that if you happen to plan something really wrong, well, nothing happens. Cars and utility veichles litterally start to DESPAWN from the road and the traffic jam goes puff. Yes the statistics go down a bit, but everything else goes on like nothing ever happened. That was the deal breaker for me