Have you seen SF hotel rates during convention season? The most basic rooms go for $3-400. Have you tried to book a Paris hotel in summer? In my experience your statement is not true
Have you tried to book an AirBnb during a marathon? The most basic room goes for $200/night, before you add in the "cleaning" fees or the "service fees" or the other "fees" that hotels are required by law in their original quotes.