On the other hand, if your priority is to create a profitable entertainment product, and you'd like to capitalize on the enticement of a well-designed in-game purchasing system, then you should go all the way. If it's to succeed financially, the purchasing aspect of the game has to be the core in which all major design decisions are measured against. If you want to switch to a traditional single-sale system, you have to alter the game design in extreme ways.
Business models are not interchangeable within games, because a freemium system is inextricably tied to the game design.
As someone who hopes to see more games that are made first as a game, and second as a product, I'd like to say that a quality-first focus can carry your game to success, if you have the ability to execute. As long as you don't overextend yourself, like the blog post stated, you should be able to continue making hits if you can maintain quality in design and execution.