Back in the Nokia brick days you could easily go a full week between charges.
Of course it's an apples to oranges comparison since a modern smartphone has infinitely more functionality, but in this one thing modern phones remain objectively worse.
Does it, though? Unless you go back so far you're talking about fixed–layout b&w LCD screens, the next era after that had games and the internet — what's actually new since that time? Multitasking yes, what else?
You can still go a week on a modern phone if you restrict your usage to what you would do on a Nokia brick phone.
You have to compare the old Nokia phone with the new Nokia dump phone. I doubt that the old phone's battery lasts longer than that of a new Nokia 2720 Flip:
https://en.wikipedia.org/wiki/Nokia_2720_Flip
The new dump phone likely has more functionality and uses a much more robust wireless network.