Zompist Bboard Again

I may possibly be in a situation where I could use your Maraille setting in an rpg campaign in a few months (or maybe it won't happen, but I will be moving to another state and was talking about the topic with someone who is moving to the same place.) I got thinking about stuff probably beyond the scope of any campaign I would set up and am curious how much longer you envision the jondiles being able to maintain low tech on the rest of the planet? I assume that, given sufficient motivation on the part of the jondiles, they could maintain it indefinitely, but mention is made on the relevant page of your site that a growing number are starting to reconsider the whole idea - perhaps a small segment of the population as of 4901 but more than 0 people and implicitly growing if it's now an idea under discussion.
I can see a couple of ways it could go if the lid is taken off of planet-wide tech development. (I assume socionomics would have suggestions on how to proceed but I unfortunately have not received my PhD in socionomics yet, alas.)
1. Uplift the low tech societies as fast as possible. Fly our hovercars over to the main continents, tell them what's up, give them some batteries and stuff and try and get a society using 50th century technology within one or two generations or something like that.
2. Stop capping tech development but don't actually overtly interfere or give them 50th century stuff. Just let them move on from 15th century stuff and let them advance slowly as they figure things out, over the course of a few centuries, and hope that you can successfully intervene if necessary when they find out about nukes and are possibly considering using a few nukes on those bad bad people over there.
3. Removing the tech cap is unintentional due to internal political divisions on Ile de Maraille. There are a bunch of people who are in favor of keeping medieval society on the planet and a bunch of people who aren't and things get out of hand and we get something in between options 1 and 2 because partisans are fighting each other and unable to effectively achieve their desired goals but definitely are able to ensure the old status quo is no longer the case.
4. Removing the tech cap is removed because some disaster causes the jondiles to be either unwilling or unable to enforce it. An asteroid hits their island or they all die of covid or something, and couldn't even enforce the tech cap if they wanted to. This is basically 2 except they don't have the option of intervening if they see the low tech people doing something inadvisable.
5. Maybe I missed something and there's another way this could play out, assuming that the tech cap was removed at all. (Obviously all these options assume the tech cap is being removed for some reason.)

These seem like the ways it can play out once a decision gets made to remove the tech cap but I don't know how close the tech cap is to being removed. From a Doylist world building point of view, I am amused by the idea of the tech cap lasting long enough for fully fledged language families to emerge, rather than a handful of languages with immense dialectical variation, but morally speaking*, I would be a supporter of removing the tech cap in some prudent way if I were a member of jondile society.

*This is definitely a fun idea to work with for worldbuilding purposes and I am in no way judging anyone for having the idea or for thinking it would be a fun setting in which to write a story or do an rpg. My moral stance is solely about what I would think if the setting were actually real.

I hope you can get a RPG campaign going-- if you do, tell me how it goes!

You're welcome to play with the setting as you see fit-- it may not be canonical, but the important thing is a fun experience for you and the players. (Too much lore confuses players anyway.)

Since you ask, though, the Incatena way would be #1. Socionomics has a lot to say about development (the process of starting and growing a colony is not too dissimilar), and usually problems can be anticipated and dealt with at a deeper level. Obviously you'd need massive education, and a complete replacement of economic systems; this would be done with full commitment and an understanding of how culture shock works and how to reduce it. (Pro tip: people are much more open to change when it results in fast, measurable improvements to their lifestyle.)

But the Jondiles are in charge, and they might well prefer #2. There is a case to be made for keeping things slow, especially since Jondiles live for centuries and think of the long term. (However, if a pro-development faction has recently taken charge, they might prefer #1 to create a fait accompli, so the anti-development people couldn't reverse the change next time they're in power. Jondiles are human too, and may have serious reservations about, in effect, losing their power over the planet.)

On a narrative level, I kind of hope you'd use all this as a slow background arc, maybe unsuspected by the players to start with. If you have a fast transition to 50C tech, you're playing an SF game, which is fine but you could do that on any futuristic planet.

Definitely seems plausible. I figured the Incatena might lean towards #1 but I wasn't entirely sure how fast it could be done, and I don't know if you envisioned the canonical version of Maraille as having support for #1 any time soon anyway.
If I do start a campaign, I am likely to aim for something like what you suggest about not upgrading tech too fast and keeping Ile de Maraille politics obscured but influential, as I rather like the idea of keeping the players in the primitive environment and dropping in the occasional laser rather than giving them access to a droid army and light sabers rapidly. If it ends up happening, I will try to make sure to come back with a report. I did briefly entertain a friend with a text message campaign in the setting a while ago but it basically was a flash in the pan where I threw his knight at some dinosaurs, Odorode, and a wizard in a tie die tshirt who rapidly killed him. Whole exchange probably added up to 30 minutes if you subtracted real world constraints which delayed our responses to each other.