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?