Might just be a lot of red tape on the system (would not suprise me, UK and all) stopping little companies. I've never heard of a "big" construction company in Australia for suburban homes. They're usually middle size companies, which sometimes might use a design from a bigger company under licence.
You might not need a socialist idea to get those big companies out, just a big review of all the red tape that might make it impossible for the smaller companies, which is essentially a free market idea that promotes competition and gets rid of Big $. Too many people seem to see libertarians like myself as for big business, actually it's really quite the opposite. Big government is the best friend big business has. Without all the red tape they're doomed to mediocrity.