Mistwell
Crusty Old Meatwad
It's a cost issue. Breastplate is 400 gp. You're not typically buying that at level 3. I still have a PC around level 7 who can only a that point even consider buying anything more expensive than scale or chain mail. None of the guidelines for wealth would match level 3 for the types of expenses you're talking about.everything else is level 1 or 2 filler until you buy yourself armor you want/need; padded, leather, hide, chain shirt, scale mail, ring mail, chain mail and split are waste of space in PHB.
Regardless, if you're going to change it the ADD INTERESTING PROPERTIES. Why would you make it simply a sterile scaling chart?