The good news is that it looks like Apple might have an answer to that problem thanks to a recently published patent. According to the patent, it seems that Apple might have the answer to the dirt problem, which either involves sealing off any unwanted gaps (which also might have the potential to make it water-resistant), or introduce a membrane underneath each key that would blow out air everytime a key is pressed, which in turn will hopefully blow out any unwanted debris that might have got caught underneath.
The patent also sees Apple acknowledge the debris problem as they note, “residues from such liquids, such as sugar, may corrode or block electrical contacts [and] prevent key movement by bonding moving parts.” However given that the patent was filed in 2016, it means that it has been a while since Apple has filed it and given that we haven’t really seen this new feature in any of the new MacBook laptops, it is unclear if Apple plans to move ahead with it or if it will simply continue to exist as merely an idea.