This is the unintuitive thing about growth stage companies and just the scale that internet companies can achieve today. They might already have a million users who are happy with how it works and would rather that the UI didn't change. But they are on track to grow to 100 million users, and so if making things a little bit more flashy improves the new user activation rate by a small percentage for the next 99 million users, that can dwarf the preferences of the existing users. Especially if the existing users grumble for a few days but then mostly continue using the product.