When Did This Happen?

So, I rolled up a Pally for quick adventure and was fighting couple of skeletons.  I was losing but still in the fight and it dawned on me that I should be able to turn the undead.  So I looked in the 5 edition player manual rules and found nothing.  But on page 22 of my Player's manual, that was printed in 1978, it said that at level 3 I was about to effect the undead, demons, and devils. Poor me I was only level 1.   So when did this change happened and why still can't we effect the undead, demons, and devils?

Turn Undead now purely a cleric thing (at least in the PHB... not sure about other sources), though all Paladins have Divine Sense and Devotion Paladins have Holy Ward as part of their capstone. In addition, Divine Smite gets extra damage against Fiends and Undead, so there is still a bit of that "anti-evil" thing there.

Paladins also have Divine Sense as a use for their Channel Divinity which lets them sense Celestials, Fiends, and Undead. Might not be as powerful as Turn Undead, but it is still useful.

I do agree with you about the 5 edition PHB, however in the 1 edition PHB it wasn't solely a cleric thing. It worked for booth classed.  I tried to post a picture of from the 1st edition, but I had troubles loading the picture.

https://imgur.com/a/first-edition-pally-ieIQhRc