Hey man firstly great article with good info.
I find decentralized apps are less popular due to less advertisements. In a centralized platform there is a team which works outs it's job of advertising in various crypto related websites and apps. The lack of ads makes it less popular because a user will never come to know more about it unless redirected.
Also the threat the EOS gambling websites are facing from hacks makes it quite dangerous to use. I am sure as blockchain improves over time the EOS platform will undergo huge changes.
Personally I don't and will not play such games because gambling is gambling!!!
I think they should work on their advertising!
Second question what should EOS jacks do to remain in popularity.
The answer according to me is continue incentives scheme but reduce it over time and then finally remove it. This period should take at a very gradual pace so that people may not lose interest suddenly and leave but get them addicted and slowly reduce and then eventually remove the rewards systems.