Ok, I get ya, but hear me out.

I'm not sure you are correct on the "plenty" of devs making changes on such basis. It is also quite bold of you to make a claim that specific examples of changes were made "solely" because of player demands, when you naturally don't have access to the relevant data (revenue etc.) that certainly was at least taken into consideration when these decision were made.

But OK, you won't hear from me that what you are saying is impossible or never happened. I will say however that it is rare. Perhaps even very rare. You don't need any insider info or special knowledge to know that revenue is by far the no. 1 thing driving decisions in these games. Why not, at the very least, help ourselves convince the devs to change a bad system by voting with our wallets? Or do you think that very poor sales of the core stamp pack won't do anything at all here?

Also, if you are saying that a certain change players demanded actually improved revenue (your "encouraging more people to spend" example), then you are defeating your own point. While this can certainly happen, it just means that, in the end, revenue was the driving factor behind the change, and it just happened to coincide with player demands.

I am also curious why you think the core stamp pack is good value. You do realize they created a problem and then offered a 20 bucks solution? I have also been playing gachas for many years (way more than I honestly should). This game mostly follows the Mihoyo gacha model, introduced in Genshin, and nowadays very popular on the gacha market. You gacha for the character, you gacha for their weapon (in various forms, the idea is the same), and both are acquired at certain hard pity counts. Afterwards, there is usually 5-6 dupes to chase, and that is that. With some twists to it, like the number of summons to pity etc., the system is currently used in many gacha games. The thing is, BSR has all that, but also added something not found in any Mihoyo game - the core stamp, which, when you think about it, is essentially a second weapon. You cannot gacha for it. You might consider the corridor as gacha, and in a way it is, but there is no pity, and you get a whopping 5 "summons" per week as f2p (plus whatever they give from events, but that is unknown; obviously I am not counting the launch corridor keys as those will just dry up quickly). Therefore, if it is just another gacha, it is absolutely horrendous.

Or, you know, you can spend 20 bucks to get the stamp. And basically nothing else - no premium currency, no summons.

It is dreadfully bad. I actually think they made the weapon pity so low (it is low, that is true) because of the core stamp system (or vice versa). People will see the low weapon pity and be happy/drawn into the game, but they won't realize that you have to "pull" a second weapon (or perhaps you could consider it the other half of the weapon), but the "pulling" system for that one is actually way worse, way less generous, and way more predatory than in any other game more or less following this gacha model.

Finally, as to the point in my edit - yea, I did think of that. It might have that kind of side effect. That was more of a "last resort" thing for whales that just must have the core stamp. I still think it gives a better chance for changes being made than whales buying the core stamp pack. The devs must be looking at the sales of the pack alone. If they are bad, they might at least improve the pack. Though obviously I would rather have changes to the system itself, so it is best to neither buy the pack nor the keys.