That's so stupid...
Brian, what happens on all those swept back planes that are never intened to break Mach? Sweeping a wing has to with peformance, more sweep, less drag, higher Vmo speeds for a given max thrust is one perameter...but one get's higher stall speeds in the clean configuration...they get that back with flaps, slats, ect...so they can land with that swept wing. If you sweep a wing too much, take off and landing distances can get unrealisticaly long and also maybe the engines needed can't push such a low drag, low lift wing through the air to carry the load desired. There is a place where the amount of sweep, the lift devices available, the load desired, the engines installed, altitudes flown, fuel amount burned and carried...all add up to a plane that can take off and land at acceptable speeds and distances, fly for acceptable ranges, have decent handling chararistics that Joe Pilot Typed Yesterday can fly it, and carry a few people in back that are paying for all this in a safe, fast enough, efficient enough manner. All while complying with all the FAA type certificated requirements that planes need to go through.