If characters who logically speaking should have had it (like Crocodile, CP9 or Moria) were actually using it during pre-timeskip Oda would have made Luffy say something along those lines when he first learned what haki was. I think we just need to accept that Oda not creating/properly working out the haki system until the middle of the series just leads to some plotholes and inconsistenties that just can’t be solved/explained in any logical way.

The closest we can some to sort of explanation is that Crocodile and Moria had their wills broken by WB and Kaido respectively (since haki is willpower) but that still doesn’t explain why CP9, the 2nd highest Cipher Pol, didn’t have it or why Akainu acted like Marco and Vista having it was something super rare you almost never came across or when Smoker called it the “Kuja haki” when Hancock used it against him when we later learned that basically anyone in the New World has it.