Hmmmm it really depends. I don't come from the world of ballet, but from another high performance endeavour where you have to invest a lot of time in your teens.
If your child wants to do ballet just as a hobby, then of course it is probably too much.
If your child wants to excel... Any child that I have known to excel, unless they are lucky to live in one of the relevant performance hubs, they have travelled extensively around the world and done long camps with the training group from age 12 onwards. Many I know have moved away from their family before age 16 to live with another family permanently and pursue their activity. Alternatively the whole family has relocated, e.g. from the US to Italy. One of the kids I was with moved from Korea to Europe at 11, she is now one of the best in the world. Elite performance really does require commitment and sacrifice, total dedication to the craft.
Ultimately if you want to be world class, you have to find the best coaches/teachers and conditions. This is why, for example, you do not see many people from obscure countries excel in the olympics unless the country is a performance hub for that sport. If you do, their parents are obsessive, e.g. Williams sisters.
You may find this useful: https://www.waterstones.com/book/the-gold-mine-effect/rasmus-ankersen/9781848317109
Look at the former principal dancers of the RBO or National... A lot of them left home at 12-16.
A ballet 'camp' would be total immersion. Intensive classes, sharing with other students, learning about recovery, fitness, nutrition, traditions, mindfulness... It's also exciting to meet other high performers... To be honest time with family at the end of every day would be a massive distraction to performance, and even learning about other cultures.
Generally though, don't kids leave home for long periods of time anymore? During my upbringing, it was normal to be away from your home and parents several weeks a year for various reasons, e.g. sport camps, fun summer camps, school trips away or abroad, away with your sports team, study abroad, visiting family etc, from age 8. Nearly everyone from my family did this, some even went away for 3-6 months, or even longer.
Do i sound like a Russian performance coach yet? 😆I'm not, but for all the talk about 'treating children like children', the ones that do excel at the highest levels unfortunately still do display an extreme dedication.
If you want your child to have a normal childhood and stay close to home, it's better to keep ballet as a fun hobby and focus on education.