See, I still disagree. Working with WordPress has been nothing but (relatively) easy for me, even when making relatively complex plugins.

No one is arguing that WordPress is better, necessarily, than a custom build. But reality trumps theory. Theoretically a perfect diet may be out there, but if you can't afford it and won't adhere to it, for example, a less-theoretically-perfect diet that you can afford and can actually follow is better.

A lot of times I or my client can't afford a developer for a custom app. WordPress solves that problem, and I think it's only getting better, simpler, and more stable with time (as all open-source projects kinda do).