There are three popular "theories" why keys fail on MBPs. Note that these are just theories and we can't know for sure, really.
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Heat. The most popular one, the idea is that heat causes the butterfly mechanism to change (which does make sense in a way, materials grow under heat) making the keys unresponsive or "double" pressing.
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Dust. Small dust particles get into the mechanism and create issues. This certainly happens to some people, but it's not necessarily the cause of all problems. For example, if some dust gets captured in a key and it's physically hard to press as a result, blowing it out with compressed air can solve the issue. I've heard reliable reports of this happening and air solving it. However, while it does solve issues with physically pressing a key, I had an issue with spacebar double registering and cleaning it didn't help (they removed the key in service, cleaned it, and put a new button with no result).
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Force. Some claim that hitting the key too hard may cause the butterfly mechanism to deform.
Also, it could be something else entirely.
As I am aware, keys on MacBooks that have 1st generation butterfly keyboard don't have so many issues other than dirt. I haven't heard so many complaints about double-presses though. So I'm guessing it's not just the dust, it's heat or force (or something else).
My MBP had the top replaced with the new, 2017 keyboard. It feels slightly different, so I can imagine the mechanism is made out of slightly different material, or in a different way. People here compared keycaps and said the difference is there, however, before the top replacement, they replaced a few keys with the new keycaps, and the feeling was identical. So, I'm guessing the change, if there is any, is "deeper". I can only hope that it is more resistant to temperature changes or whatever is causing the issue.
I love the new MBPs and the 2016 redesign. Would I advise against buying one because of the keyboard issues? No. But I do advise getting AppleCare. Manufacturers do make tweaks in the manufacturing process, and I do hope that Apple has fixed or at least greatly reduced the issue. I doubt they are preparing for 2018 revision (that reportedly has the same design) with this remaining a problem. So, a 2016 MBP with AppleCare can have the latest top case replacement if the issues arise.
If you have AppleCare and have issues, try to get your top replaced. Do not try to fix the issue with fan controls or anything similar! That is not a long term solution!
If you don't have AppleCare, you have to pay for service. You will pay a lot (a 600-700 euro part in Europe), but at least you get a whole top replacement that has a new battery, new metal housing, new Touch Bar, etc, so at least there is some consolation there. My advice to anyone that have issues out of warranty is to somehow live with it until the 2018. models come out. While I do believe if there is a fix, Apple already fixed it, it's still safer to wait a few months if you can and be sure you get the latest iterration of the keyboard. Also, since you'll be getting a new battery as well, why not strech it a little? Again, it's a LOT of money, but at least the battery will be new, and any scratches or dents you made on the top case will be gone, so you at least have that. In the meantime, if your keyboard is doing double registering - you can use BetterTouchTool to remedy that on the software side (while you wait, like the fan control, this is not a long term solution!)
And press Apple. Write to them. Send polite feedback. If you're under AppleCare, send it for service and ask for top replacements. Believe me, a 700 euro bill charged to Apple sends a much better message than forum rants
Note that while I understand your anger, "fire Tim Cook" messages to Apple will get you nowhere. I know it's tough to swallow, but advanced design can have design issues (remember all those Surface Pros issues?). So, make sure you're heard and hope for the best.
