Personally, I don't like to block PCs out of skill checks - particularly when there's no specific reason that something should only be doable or known by someone with proficiency in the skill. What I do is try to deliver the information in a way that's relevant to their different backgrounds or classes. And if the cleric blows the check to recognize the obscure holy symbol, I'll still try to give them some info about it such as the portfolios implied by the imagery. If another character, like the rogue with a street urchin background, makes a luckier roll - I'll imply they learned the info in a way that would fit - perhaps seeing someone in an alleyway with the symbol and hearing scuttlebutt about what it's for. Or, if I'm the player and the DM isn't very detailed about that, then I will couch it in those terms. "Oh, yeah, I heard a story about that once..."
This way, I don't rely on rigid niche protection, but I don't blatantly overshadow the character who's supposed to be good at it but didn't roll as well.