I have a different view of track bars and have had the SAME experience that you described... the rear axle mount point cracked thus releasing the track bar. In my case, I had the mount welded and re-enforced and had the track bar reconnected. Like you, I want to keep the Jeep as structurally stock as possible. The weld has held just fine for six years now. By the way, I have NO lift of any kind on this 1990 YJ. All of my suspension geometry is stock.
If it should fail again and it can't be re-welded, I would consider replacing the entire axle for two reasons. 1.) That axle was last installed at the factory in 1990 with no maintenance other than gearbox oil changes. It's due. 2.) I consider the rear track bar essential to the safe and prolonged operation of the vehicle.
Consider the fact that these brackets do crack and fail... that by itself tells you that there is some load being reacted by that track bar. And, while the function (or non-function) of the front and rear track bars is debated, I find that the "torsion spring" function of that bar is often ignored.
In my case, the symptom I had leading to the discovery of the broken bracket was a structural "thump" when accelerating or braking. When accelerating, the engine torque is obviously delivered to the rear wheels. Since every action has a reaction, the "forward force" transmitted to the road surface causes the entire axle to wind up, or, to rotate along the axle lateral axis. That "forward force" is carried to the Jeep primarily through the rear springs to their frame mount points. With the rear track bar "unhooked", that axle rotation is no longer damped by the Torsion Spring track bar function. The axle rotation torque is then reacted by the spring U-Bolts holding the axle to the spring and by the rear shock absorbers. The load on the rear springs is not in the conventional "up and down" or "fore and aft" direction, but in a rotation tending to push the front of the springs down and the rear of the spring up. This is normal up to point and when the U-Bolts are tight doing their job, but the track bar torsion function also dampens these forces. Everything is opposite when applying the brakes. The entire rear differential tips up and down, again not so much in the "bounce" direction, but around the axle lateral axis, placing some additional stress on the drive train universal joints. So, the thump I encountered was the result of things being more free to move and interact during acceleration and braking.
Another indication that the track bars (front and rear) are working for you and transferring loads becomes evident when removing or installing these bars. I watched a YouTube video of a guy showing how to remove his YJ front track bar, and he worked very hard to "pound out" the first of two bolts. It was TIGHT and he had to use a large punch and hammer. Like 90% of Jeep owners, he had jacked the Jeep and placed jack stands under the frame to carry the weight of the vehicle. I wrote him to point out that if he had the tires up on ramps, OR, had the jack stands under the axle, those track bar bolts would come out (and install) easily by hand. The requirement is that the weight of the vehicle be carried by the springs when working on track bars. I've done it myself when replacing the front track bar due to worn rubber ends. (You can buy an entirely new front track bar for $60 to $70 dollars). The point is, as the Jeep bounces along your chosen path, the track bars continually tighten and relax helping to regulate your suspension (and steering) geometry.
Lastly, and I hate this one, IF you are involved in a serious accident and the issue arises that the Jeep suspension had been "compromised" by intentionally removing these factory components (track bars), many insurance companies will use this data to unload their financial responsibility. This is particularly true in death or severe injury cases. It will be up to you to convince a court that track bar removal had no bearing on the event. This would not likely be an issue with most routine accidents involving minor property damage.
