Thank you, I had the same question.
I seem to remember that in the Siddur Sfas Emes (The Roedelheim – classic yekkish siddur) the parshiyos, except for the tomid, are printed in smaller print or without nekudos, indicating that it is a relatively new minhag, as opposed to eizehu mekomon which is an old minhag. (When you say relatively new regarding yekkish minhogim, it means after the Mahari”l, so very early acharonim.)
I will bl”n check it up and post again.