I get it, but I don't agree that the defense is having a smaller number of tldns. I think the problem is with an omnibar in the first place, because it has to heuristically guess what you want. I preferred having a separate search bar from address bar.
For a technical professional, I fight with the behavior of my web browser's address bar far more often than I really think I should. Maybe the average person would be far better served if the browser only assumed you meant a URL if you explicitly included a scheme, and otherwise just did a search.
The omnibar is a mixed bag from a usability standpoint. It favors the bold and confuses the meek. For some non-expert users, they eagerly mash in whatever they want, without understanding that the browser treats "hot women near me" differently from "amazon.com". For other non-expert users, they see domain names and big scary URLs in the omnibar and are scared to type anything into it that isn't an "official" web site address.
For a technical professional, I fight with the behavior of my web browser's address bar far more often than I really think I should. Maybe the average person would be far better served if the browser only assumed you meant a URL if you explicitly included a scheme, and otherwise just did a search.