Loopin' Louie? The modern one's lighter and has a weaker motor, even if the original was never exactly greatest-games-of-all-time material, the modern one's just non-functional.
Rock 'em sock 'em robots? Weaker punches, plastic's lighter, new models are often smaller. They suck compared to vintage ones.
Hell even soda bottles are kinda like this. Those things used to be thick and you could re-use them for all kinds of stuff.
It seems like at some point around the late '90s and early '00s we got a ton better at precisely optimizing plastic use in mass manufacturing processes, and all plastic products got somewhere between a little, and a lot, worse, because manufacturers could make them just barely thick enough to not fall apart. Good for waste on the one hand, for disposable things, so that hits "reduce" at the expense of making "re-use" a lot worse. But also makes non-disposable things so shitty they become disposable (often because they suck so bad to begin with that you're gonna toss them out after one use)