We're ALL "free" players in this. There's no subscription service. It's entirely voluntary if and when we choose to support the devs a bit with a purchase. An argument could be made though that more people might feel like paying and/or people might feel like paying more often if the prices were lower...

Regardless, those who would prefer not to pay do know that there's a selection of content that they just won't be getting. (At least not often. There are some free kobans that we can chase after and slowly save up.) The devs will handle that portion of the game in whatever way they feel makes the most business sense for them, we'll grumble about it a bit because it doesn't look too good from our end, but ultimately many of us will mostly ignore that portion of the game since it would be too absurd to be a completionist about it.

Ideas are thrown around, offered up for the devs' consideration, trying to smooth over the RNG of the standard portion of the game. The part that doesn't require kobans, just time. Random is random, of course. If the odds of something are 1 out of 100, in theory it should take around 100 rolls to get it but you'll have some players getting it at roll number 97 or 103 or 85 or 125 or 21 or 842 or whatever. The majority should fall closer to 100, but there will be outliers.

Anyway, I don't know what the chances are for girls to drop. I think I saw a post saying around 1 in 300? But sometimes you get on the low end of the curve and amazing luck delivers to you one or perhaps even both event drops (plus maybe even a non-event drop) all within the first day or two of the event, and sometimes you get on the high end of the curve and abysmal luck sees you trying dozens upon dozens of times every single day through the entire run of the event without any drops at all. And it is extremely frustrating when you're on that high end of the curve.

It is for those rougher streaks of bad luck that people propose ideas like "pity counters" to alter the chances after multiple failed attempts or "event token" drops to collect with better drop chances than the instant-win drop but needing to save up a bunch of them before you can use those to purchase that drop. Ideally the balance on such an idea would be that it will not take much longer to get the drop from this "shortcut" than it ought to take for an average case of lucking out on the instant-win drop right around the expected number of attempts. (Perhaps even aiming for a balance where you could realistically only expect to earn enough tokens for one of the two that you're trying to get from the bosses, still relying on luck to instant-win the other one.) A case of better luck on getting the girl to drop will see that result before the alternative can be used. The alternative would exist for the case where someone just isn't having that kind of luck.

Now this topic's original post does try suggest a way to revamp all aspects of the game into a more unified bigger picture, meaning that it is tinkering with both the "premium" and the "standard".... I think? Wait, no, he specifically said that some girls would continue to be pachinko exclusive (but they'd always be possible drops and they'd just be much more likely to drop from the pachinko during their event than they are outside of it) and the "black market" selection would be limited to the event girls who are NOT designated as pachinko exclusives. So the divide between "premium" content and "standard" content is still there.

Anyway, since the idea suggested a token reward/drop which would also be possible to pay kobans for, the balance of all the costs and drop rates of such a plan would be subject to heavy scrutiny by the devs if they consider it. They might have their own ideas about how much things should cost and how hard it should be to save up the tokens to buy something, as well as whether or not they'd agree with the topic creator's idea to draw a line where event variations of existing girls would be pachinko exclusive and only the brand new girls would appear in the black market (maybe the devs would want it the other way around as thanks for those who do buy kobans).

I'm pretty sure the topic creator gets that his values are examples and up for debate, that they're not an absolute final word on what should be used.