I have seen this also in other styles of RP as well. Last summer, while I was more or less "away" from the baroque monde, I watched with some detachment as several acquaintances built a medieval-ish village on certain lines ... and then two weeks after their sim had opened, a girl who had previously been affiliated with *that* RP, and her partner, began a second RP on almost identical lines, only slightly changed, and with a very similar name. To say it was annoying was an understatement. Steampunk, Gor, sci-fi, oh yes, now I recall a Roman copycat ... it happens everywhere. The best thing is to create something new, in the same genre as someone else is fine but if the exact thing you want has already been taken ... unless (and this is the only ONLY reason I could ever imagine for "stepping on toes", and all the same the new group would be well advised at all times to be on terms of friendship with the group which existed first) one is ABSOLUTELY certain that in builds, RP roles and scenes, tone, overall quality, all of one's proposed new RP would be UNQUESTIONABLY superior to what already exists ... just stay away.
What I have long observed, in our little world, is that so many of us want to be (for example) Marie-Antoinette. Be the star, have the top billing! But how many people want to actually do the research and role-play that role requires? In the sense of learning the courtiers, so that one knows them by their SL names and can then address them properly (Comtesse, Your Grace, Your Highness, etc.) and refer to others in conversation? As indeed is expected. Or limit themselves to what is known historically of this person, her character and ways of being, while still portraying her in a faithful way, and communicating her being and personality in the role play? Playing any famous personage isn't all cakes and gowns, or whiskey and swords, it's hard work, enjoyable if you have the aptitude for it, but I've played historical personages and I must say the freedom I have with my little Elisabeth is much more *fun* in many ways.
One of the best courts in our short history has to have been the courts, first the duchy and then the court of the Netherlands, maintained by dear Roy and Susannah Allen. The first was a court they created, what I would call a "ficticious" court, as opposed to a strictly "historical" court based on historic figures and happenings, but which was given esteem by other courts because of the quality of RP encouraged there and of course the open hospitality which they extended to all baroque courtiers. When they chose to move into a RP of the court of the United Netherlands, I think I can say with confidence that everyone was pleased and wished them well, and that their court ceremonies were always well-attended. I have always thought that this path is one too little trod, of picking out a locale, a family, a circumstance, that does not step on another's toes, and going down it with gusto and good will. I mean nothing bad by "ficticious" and think there is far more room in our world for courts that are from the country of the mind; the Coeurs are another court that is not "exactly" or perfectly based on history, yet our world is very dependent on it, and no one thinks twice about it being "made up" because it is true, it is authentic to itself, and it is open and welcoming to other courts. Also it is the dear child of good and creative parents. These things I think are key, essential to any good and lasting court whether it fits my definition of "fictitious" or "historical".
In SL, as in RL, there are going to be few people you can trust absolutely. Time and trials will show you which persons are - and are not - worthy of trust. And, as in RL, the more successful something becomes, the more people will come around who will cause problems. Fortunately, also as in RL, the more people will also come around who will be positive contributors, who will add and not subtract and detract. Also, the nice thing about studying these courts and these time periods is, that one learns of the ladies and gentlemen who lived the high-wire act of life at court, who had enemies all around, and who learned to be kind, truly gentle (genteel), witty, charming, and pleasant ... and to slice their enemies into sushi appetizers before the enemies had a chance to strike.
Bonne chance to all, whatever your intentions ... but if you have bad intentions you'd best know the little duchesse has eyes in the back of her head!!