There could have been changes in the system that made this happens else we would have seen such high score by now. What I also do not understand till now is if playing on multiple tab was the offense of those users who were banned from the tournaments and if Duelbits even specified that as an infringement to the tournament. Maybe the new users are playing fairly and according to the rules which is why we are seeing the lower points as I don't want to believe its because of reduced interest in the tournaments. Meanwhile making profits from the tournament will not get one banned
As long they don't say anything regarding the reason the user was banned then all speculation makes sense, if someone says they don't like users getting profit from tournaments it makes sense moreover consistent profits because it can interfere with their promotion. Honestly, problems like this make forum users hesitate to join the promotion including me, I am not an active user in tournaments I only participate in some special promos but as an old user I am disappointed to see my friends' cases here.
I've just requested for an account closure and it is processed quickly. I do it because I have no more interest here since there is no more benefits that I can get by playing at duelbits since the last promo exclusion I got some time ago. Although the support say that my account can be reopened by my own request in the future but I think I will never do it due to the reason I've mentioned.