You have one, massive incumbent who innovated a lot of what we see today (Stake); multiple competitors who hold a small but notionally considerable percentage of the market (Duelbits, Gamdom, Roobet, etc); a rapidly evolving space with huge potential upside. The only thing that’s missing is the competitor that will finally give Stake a run for its money.
Stake.com is not the only one that's been doing what its been doing and I don't agree that there is an absence of competition in the Cryptocurrency market, it is just that Stake has long years of existence and they have established loyal supporters since they started back 1998, others are just building their reputation and community, their closest rival Duelbits just started 2020 but they have achieved a lot, it will be different five years from now, Stake.com is just reaping what they've planted on over 20 years of their existence, you cannot expect to beat Stake by other casinos that are 2 to 4 years in its existence.
It's because Stake and Primedice are the prime movers in crypto based casino so they already established their reputation already. Of course there are rivals that is going to come and go because it is a multi billion dollar industry. So it's hard to avoid this so called copy cats and similarities in design in games because this is a niche. And probably the same set of developers are being hired and of course same slot machine operators too.