When the original Slinky came out, it was sort of cool. It was a tight coil of flat, flexible spring-steel wire, about three inches across and probably four or five inches long at rest. If you set it on a flight of stairs and flipped the top few turns over, it would fall over the edge in a sort of solid-state siphon. Momentum would throw its last few turns over itself, and it would repeat the process, slowly walking down the staircase. You could also use a Slinky, stretched (but not overstretched), to demonstrate propagation and reflection of both displacement waves and compression waves, and with a little care, to demonstrate standing waves.
Then mini-Slinkies appeared. They were too small to walk down stairs, but could be made to walk down a pile of books of about the right height, or maybe bricks. But you could only pile a staggered pile of books just so high, and very few people kept a supply of builders' bricks around the house. All in all, there was rather less you could really do with it than even the original Slinky.
Now, you can find "Slinkies" in every dollar store -- and hardly anywhere else. They're usually mini-Slinky sized, sometimes even smaller. They're brightly colored, and made out of cheap plastic. They won't even walk down a pile of books any more. The plastic is too light and too stiff for Slinky-style walking. If you try it, the usual result is that the top few turns you tip over the edge snap immediately back onto the coil as the entire Slinkyoid topples stiffly over the edge, lands on its side, and does nothing. The cheap plastic is also fragile; they deform permanently - or snap outright - if stretched even moderate amounts.
The form has been preserved -- now in a bright rainbow of eye-catching colors!!! -- but the function is entirely gone. You can't do a thing with them. They're completely useless.
There's a metaphor in this, I'm certain.¹ I just haven't pinned down exactly what it is.
[1] Beyond the obvious that bottom-bidder manufacturing will strip all the value out of a product to save a few cents in manufacturing cost and make more money on it, until you're left with a product that you can't make any money on at all because it's completely worthless.