Interestingly enough it also seems to vary between units. The 2017 TBMBP is apparently V3 of Butterfly according to someone who worked at Apple on Reddit, who claims they tried to fix the issue.
The 2016 Retina MacBook (12") that I had was able to handle some serious crumbage and never had issues. I at some point had some real crumbly snacks over it and nothing got inside the keyboard.
Then I got a 2016 MacBook Pro (13", touch bar). Even with lighter use, and trying to keep anything getting into it, I had basically every problem with that keyboard. The only thing that fixed it was a silicone keyboard cover from Amazon, after taking all the keys off and cleaning under them. Then it never broke again because it was effectively sealed.
I wonder if the thinner MacBook has a different keyboard than the Pro (It does, I know that now). I think that might have made a big difference, since the thinner one was definitely less susceptible to pulling stuff into it. Might also have something to do with the airflow from the key going in and out.
On the plus side though, the keyboard covers impact typing a LOT less than they used to because of how thin the keyboard is.