for some reason i the notification for your second post before your first post so i missed that part. sorry if it seemed like i was restating something so you could get the point without providing something to back it up.
well, not all herbs that heal are illegal. i'm mexican and my mom has many remedies she's used on me and my brothers for when we've got hurt. cuts, sunburns and other skin conditions, headaches, stomach aches and ear infections. there are also many stores that i've gone to as a kid with my mom to buy herbs and they had a very wide variety so it all comes down to what herbs you are refering to.
I cant say much for resident evil 4 since i frankly hate where the game went from there. i did play 5 though and since it uses a buddy sistem and is action heavy, i can understand why they'd simplify things with the injection or spray or whatever it is they use on eachother when they don't have herbs as for the earlier games, there werent many places where you would get dirt on wounds. sure, there were place with dirt, but not a lot. and you were almost never knocked down onto the ground except for tyrant and boss fights.
then you also have to consider that all the fancy modern medicine would either already be looted or non existant wherever the game takes place.
i wouldnt mind if there was a game that implimented the use of a hot knife, hook and wire, or piece of cloth, but in most cases, those things would be rusted or dirty and would likely cause an infection than keep you from bleeding out or getting infected. it would probably just be easier to have the character limp for a while till they are safe and say they did it than have time taken from the player's progress to do such things or keep having pieces of the characters clothes rip to show that they cover their wounds.
and as for food... who of us hasnt felt better after eating something good when you had a hard day and suffered various injuries and fatigue from work? i know i do. it makes walking and moving your muscles easier.