sensor - Is 24MP actually matched to Full-HD Resolution when factoring in the differences on how pixels are defined?

Naive assumption: 24MP sensor vs a Full HD monitor of 2MP, sensor has much more resolution.

Second look: You sample something that is not synchronous to your sampling raster/clock, you need to respect Nyquist - so you either lose something to antialiasing or to aliasing, you end up with only half the resolution in each dimension guaranteed. Now we are at 6MP vs 2MP (unless the display actually antialiases! Also, a monitor can synchronize the pixels to their clock, a sensor can't synchronize with reality).

Trying to be too clever: A sensor defines pixels as monochrome, one R or G or B value, while the monitor is defined in triplets of monochrome pixels. Now we are at 2MP vs 2MP.

Is that the underlying reason why 24MP has become a quasi standard?

One underlying question is: If you shoot a lens that would be good for 2MP on a 24MP sensor and display it on a "2MP" screen, the result will definitely look flawed. Why?