I used to think the same thing about walking bass (that was when I was a drummer - I don't know if the two were related
) but when I switched fully to bass and eventually got into improvised music, i.e. music that doesn't have written bass parts or very few written bass parts, I came to fully appreciate the difficulty of looking at a bunch of chord symbols and playing convincing
walking bass lines in real time.
I would agree that a bunch of arrpegios one after another would sound kind of ridiculous, and so would every jazz player. A bassist who plays like that would most definitely get laughed off the bandstand.