True, all the way around. Invest in separates, so each has the room to specialize in his art (3-season tires, and winter-season tires PLUS new wheels----because I hear it's better to shrink down to a 17" rim in the snow whenever possible). ...Expensive path, but the only way to reach the envelope.
There ARE a couple of really good All-Season tires out there, but that pro-reviewer wasn't driving anything close to them. If you DO decide on an all-season,... Nokian WRG3. Got wicked reviews as being fun in cold snow, in slush, or Summer dry. That from a review is RARE.