That image is a digital rendering of the raw data, not a photo of how a CRT would render it.
CRTs were nothing if not the opposite of jagged.
I grew up on 2600 on a tv in the 70’s. Computer graphics on crts were incredibly jagged. If you used a magnifying glass on a pixel it was blurred misconverged spot because it didn’t hit the shadow mask exactly on target.
Look at that rope: https://www.deviantart.com/gameuniverso/art/Review-of-Pitfall-Atari-5200-761326088
“Blurred” is the opposite of “jagged,” though.
The jaggedness of the 2600 wasn’t because the TV itself was jagged; it was because the 2600 was so low-resolution (160x192, maximum) that it had to be upscaled – naively, with no antialiasing! – even just to get to NTSC (480 scanlines, give or take).
So yeah, when each “pixel” is three scanlines tall, of course it’s going to look jagged even after the CRT blurs it!
