Our lawn was looking puny and I've fertilized and aerated, etc, most years.
Two Yrs ago, after conferring with a buddy, I researched our local Ag College's info. For almost all soil conditions and almost all nutritional deficiency, they recommended the same thing: Add Organic stuff to the ground.
So Wife & I spent 3 Saturdays hauling our trailer to the local recycle place and purchased in bulk, a total of 6,000 pounds of composted zoo doo! It cost about $60 and has been the BEST things we've ever done for the yard.
It was well composted, so there was almost no smell. It was light and fluffy, since they'd regularly churned it in a commercial hopper unit.
It was easy to apply, just place the trailer in the center of the yard and start flinging. We raked the thickest spots to keep from burying the existing grass. Then we watered the heck out of it.
Prior to applying this, walking across our yard was like walking across a concrete drive. Now, you walk across and you can feel the springiness in the ground. It has really loosened it up.
There were some weeds that came up that we had to deal with from the hay the elephants ate, but that was easy to control.
Maybe spread some seed next spring, and topdress with organic????????
Ron