When I first joined, signature campaigns weren't really a thing.
When I joined, I didn't know signature campaigns exist.
I ant have this attestation and so I can never know what it was like but, its not unlikely that there have been a shift.
The problem as I see it is the dynamics of the forum have shifted completely to the point where the only reason people sign up anymore is to join a campaign, or a bounty, or a second campaign or bounty (or 3rd, 4th, 5th, etc.).
I'm pretty sure there are still people who sign up without knowing about signature campaigns, but it is indeed a very small minority nowadays. It's still better than before the Merit system, at least they can't get away with only spamming.
Despite the shift, it's of note that certain systems lie the trust system and even these campaigns works in ways to correct the shift and one who seeks value in things would know what the forum has to offer to be more than bounties and signature campaigns.
Though some might have joined up due to campaigns, when you get to realise the value in bitcoin to he more than the forum and the information in which gorym offers, your must likely not going to stay away from the forum without the advent of these campaigns.
People drop by here to ask questions, verify informations and call out a scam. These works and add values to the forum still.