I see a lot of companies being advised to focus exclusively on user growth, but many have no business model and must eventually make serious compromises, often

I see a lot of companies being advised to focus exclusively on user growth, but many have no business model and must eventually make serious compromises, often at their users' expense, to succeed. How often would you say companies are able to tack on a profitable business model after the fact without making such compromises? Twitter seems to be the example du jou, but there are many.