I imagine most failures of the button mechanism would be due to vibration and dirt intrusion. Aside from putting weather strip around the opening, which if done properly will cut down on vibration as well as help keep dirt and moisture out, here's another idea:
Put a small O-ring on each button shaft (a closed cell foam washer would work too, but you'd probably need to make them - I couldn't find suitable ones on line, so used O-rings for now. This helps seals the button mechanism to keep dirt and moisture out and hopefully prevent button failure, and also cuts down on vibration.
View attachment 358861