I do think people underestimate the amount fitness influencers can make, especially with 'challenges' and plans. There's always people who don't know better and think someone they follow on social media who promise them results have all the answers. You get a '6 week challenge' get 20-50 people to sign up for £2-300 a go and you're not doing too badly. A lot of the content is obviously found for free online and results will be through your own motivation but guess it works for some people to feel like part of a group and get a small amount of guidance. Add in promo posts and other streams, they can do very well. Also the whole Dubai thing, live there part of the year and pay zero income tax. So while most are having 30-40% of their income siphoned off every year, the ones who don't mind relocating to take advantage of this can then 'profit' massively.