I like the idea of tourism and think its a good way of making money....however, i have space for 19,000 tourist and probably about 500+ space ports and still cant bring in more than about 5000 tourist. Most buildings have and upgraded form that increases production. Why does the space port not? I assume the new star port will bring in tourism but am not sure since I cant find any info on it...however thats pretty late in the game. Maybe add an upgraded space port that will allow more tourism immigration to fill the spots.
Tourism isn't really worth it but the star gates also bring in tourism which come a lot earlier than the star port