Most companies (and seo experts) vastly prefer .com domains though; wether for valid reasons or not, this still is the case. Squatters make loads of money from companies getting another tld and then later buying the .com.
I get all that. It’s also not a default by any means.
Lots of places around the world do not default to the com domain name and it doesn’t make sense to treat a word without a TLD as a domain name.