Tanzania is one of the best travel destinations in the world. While tourists travel from thousands of miles to visit and marvel at the country's best attractions including the mighty Serengeti and The Kilimanjaro. Less than 5% of Tanzanians have any interest in visiting their own country's natural wonders.
I have been perplexed by the same question for years as I grew up and decided that I wouldn't be one of them...in a good way.
So my first job after college as a banker really gave me access to these destinations as I was traveling throughout the country as the country's bank MI analyst. But working as a banker sucks...you don't have time for other things, literally. So I what I was expecting to do as a domestic tourist didn't pan out because of my working environment. This was one of the major obstacles I find out why most Tanzanians were not into visiting these sites...they didn't have time to do so.
Of course, there are a lot of other reasons including the fact that Tanzanians live in a country with not so much purchasing power as most tour companies are designed to serve the foreign markets in the US & UK.