Well, let's do the math...
BTC: $7000
12 months, so you need $583 per month.
Signatures run for 2 to 3 months, so you need 4 to 6 successful signature campaigns returning 1000 / 1500 dollar each.
I've had signatures with that amount so, I'd say it is possible.
Sidenote: most signatures require 10 to 15 meaningful posts a week, so you need to find a strategy to post up to 780 posts a year here, without becoming a spammer.
Since it is realistic to say that a few of these campaigns will fail, scam you or won't earn enough, it's a good idea to do social media campaigns intensively. This may earn you an extra 200 a month, compensating the predicted loss in signature campaigns.
Hope this helps!