Honestly, the judo belt system is completely different. A dedicated judoka is usually brown or black by the time he turns 18 or 20 at most. Colored belts are for kids in judo and they don't even have to think about it, i.e. one grading every 6 months or so.
By definition, good competitive judokas started before they were 10. Young adults competing at a good level are all black belts, it doesn't mean shit. It is very rare to see good judoka who started late like in BJJ.
EDIT: just to add, the belt system in judo is not aimed at adults at all. I am a 42 y o fucking green belt. Started at 28, moved around a lot and was always just a casual hobbyist. One of my gradings like 10 years ago was not stamped in my judo pass so I had to find a partner of comparable size and level and re-do it when I changed club. Then, was on the verge of doing to grading for blue but Corona came. Now in my latest club (moved again), there is nobody available to be my uke at my level, will have to wait a full fucking year when the current orange belt adults grade for blue. And BTW my current club is one of the most inportant one in the country. On any given day you will see around 30 absolute killers between 18 and 30, but of course all black belts and competing at national and international level. To these young lions, older hobbyists like myself are the lowest of plebs and won't waste time being my uke for grading.
First off, props for starting Judo at 28 and sticking with it into your 40's. Unlike BJJ which is relatively low impact, getting bounced off the ceiling by killers scares away many guys once they're past teens. Sucks you're not getting the attention you deserve at your current club - have you considered moving to a smaller club that has more adult hobbyists?
I agree competitive Judo at national level and up isn't meant for adult novices. But it's the same in every established sport. I mean you don't see dudes starting soccer, baseball, football, basketball, hockey, wrestling, gymnastics, athletics or any other mainstream sport in their 20's and then making the Olympics or top pro teams.
The Judo belt system is about encouraging competition and rewarding results, not chasing a belt color. Want to be a hobbyist and not compete? That's fine, but you'll spend longer at each rank. Even if you compete and lose every match, you're still eligible for promotion faster than non-competitors due to (marginal) points for entering a tournament. And you earn more points for beating higher ranks, so there's an incentive to match higher belts in competition, and less points for beating lower rank so no incentive to sandbag.
Judo puts on a lot of adult novice tournaments at the local and regional levels and even the U.S. Nationals has a novice division. Novice is yonkyu and below. That generally means >3 years consistent Judo training MAYBE four and that's only if you don't compete. If you're competing regularly destroying other novices, promotion points will bump you to brown in 2 years, possibly less if you're a monster. But unless you're Mike O'Hearn, no one brags about winning a novice Judo tournament.
The other aspect the Judo belt system gets right is integrating youth and adult ranks with common sense. As you can see below, USJA adds 5 juvenile ranks that don't exist at adult senior. But once you're juvenile green (maybe 2-3 years), you're in adult belt territory and when you turn 16, you get to wear that adult belt. So if you're a juvenile brown, you put on an adult brown at 16, not an adult novice belt. If you're still a novice after training something for 10 years, your instructor sucks.
My 6 year old son is now 1 year into BJJ and is proudly rocking a gray and white belt with one stripe. I've had to explain to him that if he trains consistently for the next 10 years and goes through all 13 BJJ kid belts with fucking 4 stripes at each belt, MAYBE he'll get to wear an adult blue belt at 16 if he plays his cards right. SMDH this is why I've told him not to get fixated on belt color, only on being the best version of himself, whatever that is.
