Yeah, they are easy to repair, but I think the main point is that they are plentiful. I don't think a few little projects like this are going to put a dent in the overall market supply.
The problem is that is that the demand is already quite high at the moment (retro is cool is seems) and the supply is only finite. Given there are decent enough reproductions I feel it seems a little ill-advised hacking the irreplaceable originals as once they're gone they're gone for good.
Plus if we are completely honest, a refurbished original would also have more longevity than one with a raspberry pi which will have an initial novelty factor but then quickly get forgotten about once the Pi becomes obsolete.
At least, I hope they don't.