Well, there's no room in the Lower Mainland to build more suburbs. You can only go up. Unless you want to live in Langley or Abbotsford, but no one wants that.
There is. A lot of the bottom lands are still undeveloped (by law) like East Richmond, Most of Delta, Central Surrey, and Pitt Meadows. There's still a fair amount of less fertile Glacial Upland areas which can be tracted. You can still go up the hillsides. Public policy is largely opposed to this, but it's not impossible
As for no one wanting to live in Langley or Abbotsford, someone has to vote for Warawa
OK, there's land available. But even if public policy wasn't against developing it, it would be ridiculously expensive to live there.
Does anyone commute from beyond Hope?