Why don't we have pinball machines in the game?

Honestly, just because something was in the older games doesn't mean it has to be in Sims 4. Look at the burglars - that was a classic part of the series and it was only added back after over ten years. It shows that even for things that were always part of the game, they really take their time.

The bigger issue for me is how they handle the game in general. There are bugs that have been around for years and the devs just leave them there, even though they’re small things the community already fixed with mods. If they aren’t even fixing basic stuff, I wouldn’t expect them to care about pinball machines.

But who knows, maybe you'll get lucky and they’ll add them in a future Retro Expansion Pack or something.
Guess we’ll just have to see what happens!