I think it has more to age than profession. By your mid 30s, you probably will have a decent living space, a car, some money in the bank. At that point, why not start spending on things you enjoy?
Enjoyment can be a fancier house for some, a fancier car, or an expensive hobby. Being a whale in swgoh isnt even a terribly expensive hobby, when comparing to motorbiking, sailing etc.
Some may just put whatever tgey can into the bank account, but personally, im not a fan of that option. Those are just numbers. Whats the point of working hard if all that it changes is just some numbers in a virtual web site.