Well, the upsells aren't reliably available, first of all -- buying a TPAC ticket in E- and waiting until the day of to see if E+ is available is taking a pretty big risk. Also, the cumulative cost of upsells would start to add up over time.
I don't see why these upsells offend some elites. The $100M+ in revenue that these upsells generate is a very large reason why we still have E+ around.