Just to clear this up. Different RTP settings doesn't  mean that slot game/online casino is rigged. Online slot is/should be random operating on 97% RTP or 89% RTP.

Software providers are businesses offering their services to different online casinos & markets. Different markets/countries have different demands & operating costs. Its up to management of online casinos to decide which business model to choice and calculate costs VS profits.

On the other hand, it's up to player to choose where are the best chances to play. But the fact is that few percentage of lower RTP settings can affect player's play-time drastically in the long-term.

When I catch some extra time, will make separate thread on this subject.