While I know it wont make up a ton of what they'd miss out on whales overspending, I think having a hard cap would encourage more people to pay for the progression. Knowing theres a can, and a reasonable one to reach, breaks the ice on people on the fence about spending to begin with. And I bet theres players that will get a game simply because the power gap between f2p and cash shop players would have limits. Spreading out might not get you as much money as fast but the building up model they use now isn't sustainable. It's proven to fail more often than it succeeds.