It's not totally clear to me that shreding older models of MacBooks isn't the environmental sound thing to do.
Laptops have become massively more efficient and consume significantly less electricity. It some cases it must be better to take them out of use and replace them with more efficient modern replacements.
And instead of letting the market decide when a laptop is bound for replacement, let's force people to destroy it. Of course! Makes perfect sense! Apple is doing this because newer laptops are more energy efficient! How great of Apple! Such environment, so wow!
Case 1: it was a perfectly functioning computer but the owner wanted something new. They could hand it down, donate it directly to a charity, or sell it through a company like Gazelle.
I don't think I've gotten rid of a single computer in 10 years. I have 4 pre 2009 computers that I know are still in good use after installing a fresh copy of Windows 7 on them (thanks to an MSDN license). One of those four is a 2006 era Core Duo Mac Mini. The 2008 era Core 2 Duo is being used now as a Plex Server.
Case 2: they were returned to Apple under warranty, Apple cleaned them up and sold them refurbished. Apple has been selling refurbished devices for over 10 years.
Case 3: they weren't worth selling or refurbishing.
There is absolutely nothing stopping people from reselling old Apple products. The market has every opportunity to work just fine.
If it ended up at a recycler, it is intended to be destroyed. That's what recycling means. The plastic bottles you throw in recycling get shredded too, even though they could undoubtedly be refilled and reused.
I'm trying to be at least somewhat rational. A better way to respond, would be with data.
However, you talk about letting the market decide. But what your asking for is the opposite of letting the market decide. Apple have decided, that it's better for them to request the recyclers they work with shred the laptops.
So what's the alternative? Regulation that forces Apple to not shred laptops?
You will NEVER make up the Energy which is needed to produce a new computer by using a more efficient one. You might lower your electricity bills though.
There are costs related to recycling. A lot of energy, water etc. It's not totally free to retransform material. Reusing and repairing depending on age, condition of electronics is much more environment friendly. Use it as long as possible is the optimum (on computers and phones at least).
I'd wager that the electricity a normal laptop consumes over its lifetime doesn't even come close to the embodied energy of just its silicon. And that doesn't even account for all the poisonous crap you need to turn dirt into high-tech.
Laptops have become massively more efficient and consume significantly less electricity. It some cases it must be better to take them out of use and replace them with more efficient modern replacements.