Drag prediction in incompressible and inviscid flow?

It seems like the consensus for airfoils in incompressible and inviscid flow is that they cannot produce drag; or at least, we are not able to predict it elegantly. Thin Airfoil Theory and Vortex Panel Methods predict zero drag. I am vaguely aware of a wake momentum thickness approach to estimate drag by using control volumes and the airfoil wake flow field, but it does not seem like an elegant approach, and is much more complicated than computing lift.

I devised a method that predicts drag in an elegant way, as easy as lift, and compares well with NACA airfoil experimental data. I am having a hard time believing no one else thought of this, so I am suspicious that something is wrong with my method or I missed it in literature.