The reason I don't think they should be done in pairs is bacause the wear pattern on suspension components is different from other items that must be changed in pairs. The items I believe should be changed in pairs are brake pads, shocks, and perhaps tires. These items gradually wear out. If one is worn, the other isn't far behind.

Tie rod ends are good until they develop wear. Once they start wearing, the process avalanches. Just because one tie rod is loose, doesn't mean the other one is about to go also. The other one may stay tight for a long time. If you change the other tie rod, you'll be changing a tie rod that may have considerably more life left in it. The same for wheel bearings.

21 years ago I made the mistake of will-nilly replacing ALL suspension components on my 71 Cutlass when I was redoing the front end. The parts were good. Shortly afterward (~10K) I had to replace (again) two of the ball joints.

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95 E320 Cabriolet, 169K