If I want to track a package, I type in Google: USPS Tracking It's a quick way to pull up the right page. The USPS is already ranked #1 for this search. Yet, they are buying a Google ad to compete against their organic listing. It goes to the exact same page. The Google ad is right above their top ranked result - everybody is going to click on it instead. What an incredible waste of money!! No wonder it's so expensive to mail anything?!#%!!
I read about that some time ago where Google argued that paying for advertising when you rank #1 will increase click-through rates. Naturally, Google's interest is to get companies to pay for advertising regardless of rank so there is a bias there. http://searchengineland.com/google-...an-double-your-clicks-with-paid-search-116713 In the case you describe, the search term is for tracking, which means they already shipped a package through USPS and will not be providing new business, so that makes the advertising even that much more wasteful. Paying for advertising when you rank #1 is foolish enough I think; paying for advertising to track an already-shipped package is insane.
As it's always with the big business: They have probably allocated this much money to cover their advertising needs and that money has to be spent, no matter what. Somebody has to be in charge of their AdWords advertising department, so the person in charge just does what he/she is hired to do: crunching numbers. Or it could be what @billzo said.
The USPS is the United States Postal Service, a government agency, and is not a private business. It is losing billions of dollars a year and has increased postage rates a number of times over the years. Advertising its package tracking on Google when it ranks #1 (as it should rank since that is what was being searched for) is a complete waste of money. But you are right about businesses and their advertising budgets. They often hire ad agencies to buy their advertising for them and they really don't have a clue what they are spending money on.
The funny thing is that there is another reason that they should not be advertising their tracking function: it is horrible, compared to say UPS of FedEx. Their messages tell you almost nothing and are only updated infrequently.
I know - the tracking isn't always accurate. About a week ago I had ordered live plants and they sent them by USPS. I don't check my mailbox every day. The tracking indicated they were still days from being delivered, even after they had been sitting in my mailbox for 24 hrs. Fortunately, I happened to check and they all survived!! Mailman just dumped them in a metal locker on their sides - even with that big "Live Plants" sticker on the box. lol.