widget.com is not worth 50M as a name alone, and if it were then indeed widget.co would be worth 5M, however its more like widget.com is worth 5M with no site, and widget.co is worth 500K to a corporate for profit domain user.
2.5M today for widget.com and 250K today for widget.co, widget.net
I was just wondering whether it was worth putting much work into a .co or a buying a lesser .com or .co.uk.
You will have a difficult time trying to rank competitive phrases in the United States although you may do better in Colombia.