I'm sure they excuse it by saying, well, Wanda and Vision already have comics out there to reprint. While there's almost no solo material for Monica.
It's not a good excuse for not doing anything new, given how much "Vision & the Scarlet Witch" and "Scarlet Witch" trades have sold in the last two years. And other characters get MCU synergy even if they already have solo comics on the shelf. But a bad excuse is still an excuse...