It is much more complicated than this. Yes there are a lot of flags but there are also lots of places where there are no flags.
In my building in Barcelona there are 10 flats. 2 flats have occupants who speak Catalan as the mother tongue, 4 flats with occupants who speak Spanish as their mother tongue and 2 flats with foreign languages.
The language divide isn't always an indicator of their views, in the building there are Spanish speakers who want to vote yes, Catalan speakers that will vote no and a general consensus that everyone would just like the legal option to vote regardless of yes/no leanings.
That's not correct. In mother tongue terms, 55% of population in Catalonia has the Spanish as his tongue (mother/habitual tongue), and 35% Catalan. The "economic power" is in hands of Catalan-"ethnic" people, though. Source (official): https://www.idescat.cat/pub/?id=ed&lang=en
If I'm recalling correctly from NPR this morning, nearly 100% of Catalan people under the age of 40 speak Catalan, while very few over the age of 40 do.
This is the result of the language having been made illegal, then not illegal, then taught predominately by the school systems.
Is it possible the 55% who speak Spanish primarily fall along those demographic lines? Is it also possible that some portion of that 55% speaks both Spanish and Catalan?
Sincere question. I know very little of the situation.
100% of us speak Spanish and actually it's very common to use both languages in a conversation when more than two persons are involved :) it's just natural for most of us. Actually I learned Catalan when I was 18 so I usually speak in Spanish and it is not a problem at all... And I'm very proud of being bilingual. In any case I would love to be able to express better myself in English :)
(anecdote) That precisely describes my personal experience of people in BCN and BDN, at least as a foreigner that keeps coming back as a tourist.
I also have a friend who has been teaching English as a Foreign Language in BCN for at least a decade now, and he and his wife tell a similar story.
"In any case I would love to be able to express better myself in English" - you already have a fluent grasp of English. You spelt it's with an apostrophe which is spot on and come across as a native writer - for a given value of "native" 8) Good skills mate.
55% of population has Spanish as their mother tongue, but that's not necessarily what they speak now. Is there any poll showing what they actually speak daily?
Like I said, I've read the above official link. Multiple times, by now. Nowhere do I see a reference to the habitual language. Only to the Primera Llengua, which is
Llengua o llengües que la persona ha parlat primer a casa seva. Es considera que aquesta llengua ha estat transmesa familiarment i adquirida en el procés de socialització de l'individu.
This is not the habitual language. So, where is it?
The above official link has many sections. Here is the link for the official language poll ("Enquesta d’usos lingüístics de la població 2008"), which includes mother-initial/identification/habitual language details (official data):
EDIT: Seems like that's the old poll. There's a new one from 2013, in which both Catalan and Spanish grew as the habitual languages. It still doesn't reach 55%, though.