Skill in combat is really underappreciated in SF it seems. It's not just building or combat skill that makes a player or team good, it's a good combination of both, knowing how to use your and your enemy's base to your advantage, and knowing how to function as a team.
If you get even just two players that really know what they're doing and have teamwork with each other on the same team in a typical public game, chances are that the teamwork and coordination between those two alone will be enough to greatly sway the game in their favor. I've seen almost none of this kind of teamwork outside of Team Off, and I think we've done plenty well in pubs plenty times to where I'm justified in that "brag"