Quote: "we have chosen to make large areas of land unavailable for development" and that is a good choice. The Fraser Valley has some of the best farmland in the world and it would a lasting shame to pave it. In any case expansion of the suburbs is a stupid decision anywhere in the world, as it is a very inefficient way to provide housing, but it does provide easy profits for the industry.
 The region, including Vancouver, is very low density, there is lots of room to build more, including by building up.
Of course the provincial government has gone about it  in the wrong way, by approving more funding for highways and bridges will forcing a referendum on funding transit. One wonders why the opposite (funding transit while having a referendum on new highways spending) was not done.