I play a lot of horror games, and this is a tough place to strike a balance at in horror games with supplies. I've played games that are incredibly sparse with what they hand out to you, and games that hand them out like candy
Resident Evil 4 I think is a hard game the first time through though, because I do agree with you, the game starts throwing ammo your way a lot more after you leave the village, but then also the game racks up in difficulty and starts having more threats than just those that are bullet-related. And some of them have a lot of ammo, or are still difficult the first time.
*Spoilers in this next paragraph* For example, the Garrador. Shooting attracts his attention, and before you figure out how he works, the amount of ammo doesn't really help. The game also introduces the head bursters that can eat you in one gulp around this point, which is panic inducing. You have enemies that go invisible, dogs in the hedge maze that run out at you suddenly and quickly, there's the section with various traps like the sawblade vehicle or the the falling ceiling, the section where you're defenseless with Ashley, Verdugo who has a shit-ton of health, the section with the two el gigantes if you want to fight them both, the section shortly after with the several chainsaw enemies, and then things like The Tower or the bullet-sponge boss which is Salazar. And then after that you have those gattling gun enemies, IT, Regenerators, sections that consume up a lot of ammo like the vehicle driving section, Krauser who isn't very effective against guns.
*End spoilers*
All of these have strategies to make them easier, yes, but I would argue that while ammo drops more, since the game throws so many different and new situations at you which you need to learn as you go, it is a hard game the first time through. Not the hardest game ever or something, but I do think there's good difficulty to it, and some parts can still be tricky even with a lot of ammo and knowing what to do. I also think this game has the hardest Pro difficulty of the recent RE games, the only game that might come close is Infernal Difficulty in the recent HD version of Revelations.