I believe the drama is that firearms, especially military were absolutely NOT expected to remain in a stable environment. Rain, snow, desert heat, mud, sweat, etc. are all part of the normal working environment. Folk have been using firearms in these conditions since they were invented. One would expect that if a simple wax exterior finish would do the job, then that would be the norm after several hundred years of experience.
Instead, governments went to considerable expense even post WWII to have their overhaul facilities equiped with large tanks of warm oil, linseed or tung, generally, just to keep their weapons servicable for the maximum length of time in the field.
The US did convert to a tung oil finish in the 20th century, but the Britishand Commonwealth Nations continued to use raw linseed oil
as long as they had wood on their weapons. (Boiled linseed oil
was a substitute standard, but it doesn't penetrate as well, and can indeed build up on the surface, so it was not preferred.)
Read some of Peter Laidler's posts on his experiences in the Base Workshops in Malaysia, etc. to get an idea of how well the "inferior" RLO performed in extremely harsh conditions!