Why razor blades get dull so quickly.

Rust!..microrust..I have Japanese white steel,blue steel,R2 powdered steel and 40 year old Fridour henckels knives,every time I pull out a Japanese knife I leather the knife..just like barbers back when only carbon steel was used for straight razors,removing micro rust,those that are constantly sharpening their knives on stones are wrong,a blue steel ,white steel should stay sharp in everyday use for 5-7 years unless your hitting bone.
Same with razor blades,the coatings are to keep rust away,not for your comfort..lol.