[JJ_SO]

It's aliasing. 

And I always find it strange to wish for an extra blur filter to get nothing else than pixels out of a sensor - just blurred ones...

You must have stopped doing anything to do with computer graphics (games, art, text, lines) in the early 90's then, because after that they were done with pixelated graphics

Back in these days the resolution of screens and sensors were far below 10 MP. Even below 1 MP. Therefore it's completely useless to demand AA filters for 45+ MP sensors. The only difference to be seen is lower contrast of the sensors with AA filter in front of it and blacks are usually sort of dark grey thanks to the straylight the AA filter generates.

Apple II's "high resolution" mode was 280×192 pixel... 0.05376 MP.

I found an article in c't from 2001 when Sony introduced a display with a resolution "up to 2560 × 1920" with Sony's trinitron tube tech. Not even 5 MP. And tube monitors had a mask, Sonys trinitron tech had lengthy holes insted of circular ones, so that was their AA filter already.

Today no one would want an AA filter in front of a modern display - on the opposite, years ago Apple started with clear glass instead of matte plastic, just to deliver more sharpness.

I still don't know what's better in blurry images... and so far no on ecame up with sesor tech producing vectors instead of pixels.