Don't forget DT is not exactly expensive to fly. It is cheaper than all other airlines flying to Luanda as no one would fly it otherwise. A J class return from LAD to JNB to LAD is $1145 at present. So if you flew that once a week for a year and took advantage of DT's current US$600 round trip fare LAD to GIG to LAD and so slipped a Y class mileage run in to Rio during one of those weeks, you could acheive Gold that year!
ETA ~ If you joined SAA Voyager and flew on its cheapest J Class LAD to JNB to LAD you would achieve Star Alliance/Voyager Silver after eight flights (two months in), Star Alliance/Voyager Gold after your next six flights (now three and a bit months in) and Voyager Platinum after your next 10 flights (after about half a year) and it would only cost you about US$36,000. That is why DT's program is both hard (you have to do a lot more flights) and expensive (almost twice the price of SAA's) and arguably Star Alliance Gold/Voyager Platinum on SAA is better than Gold on DT's Umbi Umbi.
Last edited by groundops; Aug 11, 2015 at 7:38 pm
Reason: To show the difference in difficulty and expense between Voyager and Umbi Umbi