I'd chalk it up to bad luck and coincidence. In 5 years, CO has "misdirected" my bags twice, on two consecutive trips. I got them back (one the next morning, the other 3 days later) Poop happens. 4 times is a lot, but I haven't noticed any delay on my bags in like, ever. In fact, CO is the best IMO with the priority tags. Most times my bags are out by the time I reach the carrousel.

My first UA flight I had to wait for ~30 min to get my bags, although they did come out among the first. Is LAX always bad with UA, or was this an oddity?