I just listened to the latest Gruber podcast (The Talk Show) and he says that he heard (admittedly, he was not able to verify) that Apple did an internal investigation of the issue and found out that a certain alloy used in production - a metal part of the key - was not up to specifications and that it was prone to bending (a very small amount would do) that made the key much more succeptable to dirt than originally designed. They started using a new, more rigid type of alloy (newly manufactured keyboards) that reduced the failure rate significantly.
Of course, this is just "a guy I know heard from a guy he knows" thing. And also, a lot of people here would claim Apple is lying even if they gave all the details officially - so make of this what you will. However, this does seem like a plausible scenario.
1. Apple tests their products rigorously and they certainly didn't design this keyboard to give them all this trouble. If anyone thinks Apple knew this keyboard would fail but were like 'ah, **** it, just go with it' - you need to think harder. Just look at all the money they are loosing (even before the repair program). I have already said and I still believe the issue is NOT in the design, but in the manufacturing process. I'm sure Apple prototypes created by the design team were working fine.
2. Anyone who knows how things are manufactured at scale, knows that the production process gets tweaked during the product's life cycle. Machines change a bit, production gets optimized, materials sometimes change. An iPhone made in the first week and in the last week of its run are not identical - they are the same to the naked eye, but certain materials may be slighlty different, the production can be tweaked, etc. For example, supposedly Apple did some minor tweaks to iPhone 6 models after that "bendgate" started, even before they changed things with the 6S (and even then, it was mostly a material change as far as I know).
3. iFixit and people opening up their machines can't know the whole picture just by examining at the parts. Some changes are not perceivable.
4. A lot of people feel that the newer keyboards feel softer, which is in line with a more rigid metal part inside.
5. Keyboard repairs have dropped according to certain sources (as reported by Macrumors)
6. You can bet your ass Apple is doing something about this. How effective their changes are remains to be seen, but they certainly tweaked something, especially now since they offer the repair program. When all this started, I suspected that if they tweak anything, it will either be a full redesign, or a material change. It seems it's the latter. I don't expect this type of keyboard to go anywhere soon.
It's a design issue, a single grain of sand can **** the key.
https://www.extremetech.com/computi...s-vulnerable-to-single-grain-of-sand-analysis