Of course MLS plays 30ish games a season and the NBA plays 82 and MLB plays 2 million games a season.
Last season the Jazz averaged 18,680 and Real Salt Lake was close but slightly less with 18,153. I would guess that is a bit of a low season for the Jazz and it was a record high for Real. Plus the Jazz have to fill about 3 times as many games each season and have a smaller arena than Real.
I wonder how profitable they are in comparison. The Jazz arena is probably cheaper cost to the owners since it is older and smaller and they have 1/3 the number of games with ticket prices probably being cheaper on average.
But Soccer is growing very fast here and will continue to grow.