I'm sure contracting and the distribution model has plenty to do with it, but it's also a simple choice in an international tourist / business hotel as the most globally-known of beers actually produced in Prague proper. Most people who are in the Czech Republic and are as passionate about beer as you (and I, to be clear) are will not be drinking in a hotel lounge, but will more likely be out looking for the good stuff. So if the property tried harder, it may well be lost on many folks who are content to drink a simple macro brewed right across the river.
Or, maybe they are getting it for free for promotional value.
