Google beats the competition in some markets because they have so much power in other markets.

If you start a startup even in cloud photo storage, and suddenly Google Photos comes along, you’re dead. No one will fund you anymore, and you’ve basically lost.

Google has such an immense amount of network effect, and of knowledge they can gain from dominating in other markets, that if Google enters a market – unless there’s regulations or network effects that prevent this – they immediately dominate it.