"charged customers 19 yuan ($2.90 USD) per umbrella deposit and an additional half yuan ($0.07 USD) per 30 minutes"

"an umbrella costs the company 60 yuan ($8.82 USD) each to replace"

They have just sold 300,000 umbrellas. This is a brilliant sales/marketing/distribution disguised as sharing. The cost of the umbrella is for sure lower than 19 yuan. They save money on not having stores and sales personnel. Distribute the product via sharing and collect the money via the app. That's why once they have "lost" all the umbrellas, they will do it again with another batch.