Lost Package in Tempe, AZ

So I just recently moved to Tempe, AZ, about two weeks ago. I basically had to ship some of my stuff down b/c my car is tiny and couldn't fit everything I had (I also got rid of some furniture). My big ass 27" gaming monitor would not fit and I did not want to throw out the original box so I took the thing in its original box after taping it up nicely and sent it out through a UPS store in Holland, MI with $600 insurance.

It got to Tempe according to the tracking, then the tracking stated on Monday, 07/17 that it was "out for delivery" and then I waited until 7PM and gave up on it because it never got here to my new address in Tempe. So the next day the tracking status is updated to "In Transit" and the new delivery date is set to 07/18.

So I call UPS customer service and they open up a "lost package investigation".

That's where it has been since. I've called the UPS customer service and they just say "They have X business days left to find the package" and the UPS Store says "We haven't heard anything we'll let you know when we do hear anything".

I've called the UPS store every day since, and I still haven't heard squat.

Personally I think someone ganked my package considering the box very obviously listed what was inside it. But it's also a pretty large package and weighed about 22lbs so you would look very noticeable walking around with it.

But why did the tracking go from "out for delivery" to "in transit"? Obviously if it was scanned out for delivery then it was somewhere in their warehouse and one of their tracking systems should have scanned it individually, right..? Or was it part of a bulk scan in a truck?

Would appreciate any help with this.