Does Apple recycle old Macs?

Yes. See the Australia Apple Trade in site https://www.apple.com/au/trade-in/

including the following:

If your device isn’t eligible for credit, we’ll recycle it for free. No matter the model or condition, we can turn it into something good for you and good for the planet.

Yes. See the Computers in the "Select your device to get a trade-in estimate without a purchase." section of Apple Trade In - Apple

I have older products that the Australian "Trade In" offer is not interested in (17in MacBook Pro + other even older)- Does Australian Apple offer a recycling system?