This list is bias. Aside from Askgambler, The rest is unknown to me so all the casino listed as top with the respective websites doesn’t make sense.
For me, In able to become on top is the casino offers a huge budget for promotions and giveaways since all casino offers the same game from game providers. Duelbits is one of the reputable casino here that offers a very generous reward for all their promotions especially the Christmas giveaways and sportsbook odds boost.
My pick is not bias because I’m promoting them through my signature but rather due to my experience on playing in this casino for a long time.
I share the same thoughts as you. Many names on the list are unknown to the community as they don't even have a marketing campaign here or on other forums or platforms. I have never encountered any of them, even if they've existed for a long time. It is part of being the best to brand themselves and create a platform where they can interact with the gambling community.
Bets.io and Cloudbet are already present, but the others are either not here or not noticeable due to a lack of campaign. If we look at one of the largest communities of gamblers, Stake and Duelbits are very visible and they have earned the respect of the gambling industry.