While that's generally been true on a global level, the olympics have generally been profitable endeavors for American host cities. the 1984, '96 and '02 all turned a profit for host cities.[1] Further, if olympic upgrades are done responsibly the games can act as a subsidy for local improvements to mass transit, universities and other civic spaces even if the city doesn't turn a profit.

[1]https://en.wikipedia.org/wiki/Cost_of_the_Olympic_Games