To be very honest even if Starship is able to only lift 50 tons, which I’m sure they’ll be able to hit 100/150 tons eventually. The huge difference in cost would easily cover the extra times Starship would have to fly, compared to SLS. Considering each flight of a SLS will be around 4 billion dollars.
Also just extremely rude… Everyone would understand if he puts out a short message like “busy with work for the next few months”. Randomly leaving for months while people pay for something you make is crazy.