We know the PS4 had a fantastic launch, breaking previous records, but I think it's important to put this in perspective.
While the launch is certainly much better than other consoles this gen, and Sony definitely deserves credit for that. I don't think we can necessarily say it was better than older consoles.
You see, the market of people who play games has increased dramatically every gen. This is because the people who grew up with the Atari 2600 or NES have had kids, while still playing games, and now the people growing up with the SNES and N64 are having kids. Additionally, each new console presents compelling new ideas that bring new buyers into the mix.
A similar thing happens with launches, as the longer a company is around and releasing consoles, as long as they don't alienate their consumers like Sega did, their fanbase will increase each gen.
So really, no one shouldn't have seen the highest launch sales ever coming from the PS4. The console was generally regarded by Sony, Microsoft, and Nintendo fans to likely win the console generation, and like I said, the market and fanbase grow every gen.
That's not to say it wasn't notable, but if the NES or PS2 were launched with this type of market and fanbase with similar competition to what they had in their gens, you can be damn sure they would sell similar, if not higher numbers.