ItcheSrulik,
Daas Yochid: You’re right. The version of daas torah people seem to be defending is not very old. In fact, you might call it an innovation.
I don’t know many people who go to a rov instead of a doctor or a real estate agent.
Many people do take advice from a rov, who might sort through the various options and offer the best one. The Chazon Ish was well known for dispensing medical advice, as is the Skverer Rebbe YBL”T. But they never performed surgery.
Daas Torah does not mean that a gadol b’Torah is all knowing or infallible, but the refinement of character and wisdom attained by certain talmidei chachomim makes their advice more worthy of listening to than that of someone who does not possess “daas Torah”.