How do I move the cursor past the end of the line in Insert mode when using vi-style line editing on bash?

Question

In all that follows, the ^ indicates the position of the cursor.

I'm using bash on Terminal on OS X Yosemite and I'd like to use vi-style line editing:

prompt$ set -o vi
                 ^

By default it starts in vi Insert mode, so I can immediately type

prompt$ hello
             ^

Now let's say I use the left arrow key ← or H to move left:

prompt$ hello
            ^

Now I can no longer move to the right of the o in hello using either → or L:

prompt$ hello  # I can't move here anymore!
             ^

If I am to append something, I have to hit Esc then ShiftA.

This does not happen in emacs mode (set -o emacs) or on certain Linux machines (ssh'd into SLC 6.6 with bash 4.1, or natively on my friend's (I think Arch) with bash 4.3). In all of these, ← then → takes me to the end of the line where I can keep typing; on my Mac terminal I cannot unless I leave Insert mode.

This also does not happen with vim on my Mac; vim lets me move past end of lines with arrow keys in Insert mode. It's just readline vi mode.

I tried updating my bash (with Homebrew) from 3.2 to 4.3; that did not fix it.

I tried removing my .bash_profile and using an unmodified Terminal; that did not fix it. (I have some aliases and prompt modifiers in my .bash_profile.)

I have read this, this, and this. They don't have answers.

Thanks in advance for any advice!

Edit: On a Linux system where things work as I would like it to, the TERM variable gives

prompt$ echo $TERM
xterm-256color

The contents of /etc/inputrc are

# do not bell on tab-completion
#set bell-style none

set meta-flag on
set input-meta on
set convert-meta off
set output-meta on

# Completed names which are symbolic links to
# directories have a slash appended.
set mark-symlinked-directories on

$if mode=emacs

# for linux console and RH/Debian xterm
"\e[1~": beginning-of-line
"\e[4~": end-of-line
# commented out keymappings for pgup/pgdown to reach begin/end of history
#"\e[5~": beginning-of-history
#"\e[6~": end-of-history
"\e[5~": history-search-backward
"\e[6~": history-search-forward
"\e[3~": delete-char
"\e[2~": quoted-insert
"\e[5C": forward-word
"\e[5D": backward-word
"\e[1;5C": forward-word
"\e[1;5D": backward-word

# for rxvt
"\e[8~": end-of-line
"\eOc": forward-word
"\eOd": backward-word

# for non RH/Debian xterm, can't hurt for RH/DEbian xterm
"\eOH": beginning-of-line
"\eOF": end-of-line

# for freebsd console
"\e[H": beginning-of-line
"\e[F": end-of-line

Answer 1

It turns out the solution is simple: update bash to 4.3. The default bash on Macs (even Yosemite) is 3.2. (My question above says I did update and it didn't work, but I think it took a while for it to "take.")

Install Homebrew with

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

then do

brew install bash

then change your default shell path (in Terminal Preferences) to

/usr/local/bin/bash

and that's it. Check your bash version with

bash --version

and as an added bonus, you can get mode indicators!

bind 'set show-mode-in-prompt on'

and it will show a + for Insert mode and : for Command mode.