This isn't an industry - it's the whole concept. If statistics are to be believed, millennials enjoy the young, free, and single lifestyle a whole lot more than their parents did. They're waiting a lot longer to settle down - if they ever choose to settle down at all. Getting married, buying a house, and starting a family were once the expected rites of passage for everybody, but millennials seem to care nothing for tradition.
Gallup recently conducted a poll among millennials about their dating habits, and the results were surprising. Only 16% of people under 35 are married - the lowest recorded figure in history. A further 14% are living with their parents. That's far less than half. As for everybody else? If they have time for anyone else in their lives, they presumably find them on Tinder and keep things casual.