I don't think you get how mobile games with paid for elements work.
Its not in CGs interest to let players know in advance what is coming at cheaper prices, why would they want to lose out on your potential increased spending? Similarly they won't put them on sale permanently as then they won't create FOMO to buy these.
Also utter nonsense that their bottom line would increase as you've already stated that you could waste "hundreds of dollars" on them.
Seriously could you imagine it being mentioned at a CG/EA meeting?
"We're going to roadmap all our LSB packs in advance as we think that will increase our bottom-line"
"Wait, won't players who might be tempted to spend more now then just wait till they can get those characters for a fraction of the cost....won't everyone? Not to mention their will be no FOMO impulse spending from lower spenders"
Why don't you contact other companies and ask that they tell you in advance when the items you want will be on sale as it will improve their bottom line....I'm sure they wont laugh...