I think the 'successful business' part has become less relevant for investors that are just looking to exit sooner than later. The business model for many apps has become: make a product > obtain users > get hype > IPO > exit. At the exit portion, the product gets littered with ads, competition starts to catch up, and the product begins to decline.

Obviously this is pretty reductive but this is generally what I have seen as a user of many apps in the past 10 years.