The New York Times has a good article on brand extensions here.
The case is Cirque du Soleil, a service (entertainment) company.
It is owned by Chinese investment company Fosun, which also owns The Blue Man Group, and many others like, Tom Tailor, Lanvin, Wolford, Club Med, St. John, Sergio Rossi, etc.
Cirque du Soleil relied on “Zeitgeist Whisperers” to come up with ideas for brand extensions. In the 2000s those consultants called themself “Trend Scouts”.
An alternative would have been proper market research. What got Fosun started originally. And communicating within its own group companies. That way you can for example avoid perfume failure. What does circus smell like? adidas had to overcome that hurdle, when at launch people thought: “smells like old trainers? Or my gym bag”?
In general, extending your brand from services to physical products is difficult.