because that's what it costs for dinner for two at most basic bars and restaurants in a city.
a dinner date is the traditional date.
women, by and large, expect men to take them on traditional dates and pay for everything. even if you split costs, it's still expensive.
when i go out, by myself, to take myself out to dinner, a cheap dinner at a dive bar is $60. a nicer one, is double or triple that.
last time i spend less than $100 on dinner date was like a decade ago, back when things cost about half or less than they do now.