You say this and my inclination is to agree, but honestly, vanity items that look pretty are sometimes enough to incentivize spending. League of Legends comes to mind when thinking of a game that is F2P, but doesn't twist your arm to spend money. They makelotsof money.
The model for making money in LoL is merely creating extra skins for champions and accessing more champions faster. It's a great model and avoids a lot of the negative F2P design trends people are citing.
Again, this isn't necessarily the case 100% of the time. Sometimes, providing pretty vanity items, which are the same at the core, is manipulation enough. Companies do this with cars, shampoo, candy, etc.
Have you ever heard the saying, "There's more than one way to skin a cat."? The same holds true with the F2P business model.
I'm sure that the goal of anysuccessfulgame designer is to create a game that will encourage people to actually play it. So, arguing that designers make games without thinking about people playing it, is a bit disingenuous don't you think?
If there are no players, there is no one to pay you. So, the foundation of any game is having people there to play it...then you can make money.
Credit Card Portal - The Game!, doesn't sound like very much fun does it?