It's a combination of not restricting parts and not encumbering replacement parts with chips that can only be 'unlocked' by an approved servicer. Things like tractors are now sold that you literally can't repair yourself unless you hack the DRM, which is absurd.
If you can repair your stuff, then you start to buy stuff that is easier and cheaper to repair. Most commodity stuff is not all that differentiable and lower cost of ownership will be a factor.
To my knowledge most people campaigning for Right to Repair don’t want change the designs of the things we currently buy.
They just want to stop companies banning their suppliers from selling spares to consumers.
That is, most things are already reparable enough but certain firms are going out of their way to stop that happening.