Error in subsetting with $ immediately after a function in dplyr pipe

I could subset a single column with the following syntax for functions that return data.frame or list:

library(dplyr)
filter(mtcars, disp > 400)$mpg
# [1] 10.4 10.4 14.7

But this causes the following error when used in a pipe (%>%):

mtcars %>% filter(disp > 400)$mpg
# Error in .$filter(disp > 400) : 
#   3 arguments passed to '$' which requires 2

I would like to know why $ does not work when used in pipe like the above example.