Google was shutdown own big social network Google+. Why google shutdown?

The main reason behind the shutdown was data breach over 500k accounts had their personal information illegaly shared without consent.

Google is shutting down Google+ following massive data exposure. The company has admitted that user engagement on the service was low. Following a massive data exposure first reported on by The Wall Street Journal, Google announced today that it is shutting down its social network Google+ for consumers

Answer lies within you. Have you ever used Google+ as a social media plate form? Google+ was losing its popularity day by day and also it has user engagement on the service was low. I don't know about data exposure.