Why doesn’t Webb have deployment cameras

Because the group felt funding was secure enough they didn't need to appeal to the masses for a giant PR win. They say the diagnostic value over latch completion signals wasn't significant so all you're left with is the socials.

Other space initiatives like the Mars helicopter felt OK with adding consumer grade++ (minimally hardened) but I think a telescope on L2 orbit probably isn't as good as on the surface of Mars and so it would have to be significantly engineered for thermal and rad. And I've seen suggestions cabling present both vibration and thermal risk. Basically it was either built in from the getgo or else not needed. Webb is late, there's been a lot of advances in camera tech but too late for space certification I would guess.

Maybe future missions can use stuff we've learned from smartphone folded lenses, insect-eye CCD dots, pinhole cameras to be low burden, tiny, and risk free (or less risk)

I really wish the British lander hadn't crashed. I don't think having britpop and cameras on it made it crash.