Current military primary surveillance radar DOES provide altitude
For all who think that primary radar cannot indicate altitude, please look up the SPS-48 - which entered service in the U.S. Navy over 50 YEARS ago and is just a typical example of a long range 3-D radar type.
Phased array 3-D surveillance radars are common in military air defense service as we really don't like to just have interceptors go wandering around trying to determine if the bogey target is at 10K or FL450.
Now, the fair point here is that the height accuracy is definitely affected by the target range, but less than ~4K foot altitude error at 200 nm range is definitely common.
(Lonewolf50 - I was on the design team for the NTU many, many years ago. It's good to see it spoken of well.)