Hi, ribeirasacra,
Well, it certainly looks like someone is making a huge effort to generate interest in the Camino de Invierno. I have heard from some Spanish friends that the interest is definitely growing among the Spanis pilgrim community. Just based on what I see over in Portugal on the Lisbon-Porto segment, community buy-in is such a crucial component. I don't know if they're doing this, but the friends' groups could provide a lot of impetus to the growth of the Invierno by organizing short walks to introduce the community to the route.
I personally know of four people who are planning to walk the Invierno this year, if anyone wants an endorsement, just contact me! It is a beautiful walk. Buen camino, Laurie