Two strategies come to mind:
1. Be close to clients.
2. Live in a place with a favorable exchange rate and low cost of living.
If you are starting or are looking to hire a lot of other designers, being close to clients matter. Early in a relationship, you might have to take quick unplanned meetings, so proximity matters. If you are looking to hire designers, they are probably already located near potential clients (like NYC, LA, Paris, etc.).
On the other hand, if you want to have a studio of one and have a few clients, living in a low cost place makes sense. You can get a PO Box in another country to make it look like you are local. The digital tools make it easier than ever to communicate. Flying a few times a year to meet in person isn't a very big expense. Moreover, you can have a lifestyle that you probably could not afford in Finland or Paris. However, you won't be near museums and other designers.
"The key to success in this business is to find a boss who doesn't care." - Mike Rowe