How is lock-in good for anyone besides the owner?

Ben Brooks wrote this regarding what is gained by improving iCloud:

Platform lock-in. If all your data lives in iCloud and not Microsoft or Google, well you are far less likely to undertake such a large data migration.

That’s certainly great for Apple, but no one else. Lock-in is the enemy of competition. It’s why social networks don’t really have to compete over the best experience. And it’s why so many people prefer keeping their notes in plain .txt files, because it’s easily tranferable.

Lock-in is never good for users.