[diploid]

There are definitely people working towards this. Allot of 3d printable replacement parts are already on thingiverse but many have to be product-specific so it can be difficult to find exactly what you need. A perfect example is the remote control tab you mentioned which will be different on each remote control.

3D scanners have been touted as a way to solve this (scan your object, print a new one) but I don't think the resolution will be high enough any time soon to print reasonably aesthetic replacements. The real solution in my opinion is to make MCAD easier and more affordable so it's easier to design a replacement then to walk to the store.

FYI. backpack buckles can be downloaded here: http://www.thingiverse.com/derivative:1113