Get the wheels re-aligned again after crawling under there and examining the steering linkage for excess/unnecessary movement. If you had an alignment done recently, the charge should be covered but confer with management. If there is evidence of abnormal tire wear, the truck def has an alignment problem. Crawl underneath and check the moving parts with front tires and weight still on the ground. Then, Have a 2nd person turn the steering wheel while you are using hands & eyes on the moving joints & assemblies underneath the chassis, front end lifted and both tires off of the ground, and again with most of the weight and tires back on the ground, if necessary. To confirm your findings, ask the tech at the alignment shop to inform you of his locating anything requiring service or replacement BEFORE you go into any detail of your concerns. Using what you think/know as a baseline, compare the info provided to you by pros as a double check.
I would say you have a lot of diagnostic left on the table.
You stated 'the alignment seems fine,' but the eyeball test is inconclusive & weak assessment, at BEST. Plus, the tire has accelerated wear on the inside location which should be a dead giveaway. If you find any ball joints and steering links that are really obviously faulty, any and all replacements should be made before having another alignment performed. But something like a failed pitman or idler assembly, even control arm ball joints will take an exercise to diagnose so gather info from the web or obtain a workshop manual if you have intentions toward DIY evidence gathering. These suggestions go against the above where asking a tech @ time of alignment but I have no way of knowing if you are DIYer so hopefully I don't get beat on too badly I don't want to confuse you. But you should get the gist in that even if you can't or are unable to DIY repair&replace, at least have a good idea of the problem sources and the extent of work you would like to have done. At that many miles, I would be optimistic there are other serviceable items underlying a poor alignment condition.
