I'm trying to reproduce the right side of this graph from Introduction to Statistical Learning using R (Figure 7.1, p267):

Here is the code I'm using, and while the curve seems on point, the error bars do not fly off wildly for high values in my graph, but conversely get more narrow:

library(tidyverse)
library(ISLR2)
library(broom)

wage <- Wage %>%
  as_tibble() %>%
  select(age, wage) %>%
  mutate(high_inc = wage > 250)

# 7.1.B Graph (ISLR page 267)
glm(high_inc ~ poly(age, 4), data = wage, family = binomial) %>%
  broom::augment(type.predict = 'response') %>%
  cbind(wage %>% select(age)) %>%
  as_tibble() %>%
  mutate(lower = .fitted - 1.96 * .se.fit,     
         upper = .fitted + 1.96 * .se.fit) %>% # POINTWISE STANDARD ERRORS
  ggplot(aes(age, .fitted)) +
  geom_line() +
  geom_ribbon(aes(ymin = lower, ymax = upper), color = "grey", alpha = .2)

Does anyone know why this is / what I'm doing wrong?