It’s been “hidden” since Chrome v95 or something. Also, many companies might just host their web service on their main domain name.

Also, hit Ctrl+Enter in any browser and it’ll tack that right on it and goto the webpage or hit a redirect or 5…whatever their architect setup.

google.com may be a CNAME to www.google.com (for example).

The www (or whatever hostname) is just to balance the web traffic from the other Internet services, like SMTP, POP3, IMAP, FTP, etc.