It depends on the kind of game you're working on, but arguably if you're working on anything ambitious then you can't do it. Yes you can scrape by doing pointless heavy updates every frame for only 100 objects in the entire game world.
The moment you want to simulate something more interesting these walls will be hit and it will directly affect your design process though (design is ongoing as the game is built!). So if you want to be a better game developer, develop in ways that you'll hit these walls less often and limit you less.
Those updates don't need to be heavy if nothing is happening.
And as I related elsewhere, with a Ruby-based game engine it took 1000+ objects being updated every frame alongside other heavy stuff (multi-voice waveform based on-the-fly sound-synthesis, in Ruby) and actually passing each of them to the renderer, before I needed to bother to add any filtering.
And then when I did need to it was a trivial change to filter the list of objects to update. To the point where I literally just currently naively every frame does a map over every object in the level and check if they're within the viewport before doing the update.
Yes, you will sooner or later hit limits, but 1) you're likely to hit them later than you think, 2) it doesn't matter because when you do hit them you're likely to have a good idea of what characteristics to filter them by. E.g. for some games you want to update, but not render, objects outside the viewport in many situations based on other measures - e.g. Minecraft-style simulation of mobs within a certain distance of the player; for other games once an object is off-screen it can cease to exist instantly. But it takes consideration, and you might as well defer that consideration until you need to, because it's orthogonal to the actual update.
The moment you want to simulate something more interesting these walls will be hit and it will directly affect your design process though (design is ongoing as the game is built!). So if you want to be a better game developer, develop in ways that you'll hit these walls less often and limit you less.