I can't vote, but here's my opinion anyway:
The real issue is, do we preserve open space for its own sake? Or do we, as humans have always done in the face of various pressures (increasing population, needed infrastructure, expanded revenue etc.), find a "higher" use for it?
The value of open space is it can grow food, percolate and possibly store water, remove pollutants from the air (especially if none are being generated by a "higher" uses!), provide pleasing scenery, nurture wildlife, and offer recreational opportunities. Too often we overlook these benefits. Not enough is being said in defense of leaving well enough alone.
Do we need more shopping? Is there never such a thing as enough? Instead of letting developers dictate what we need, we should pare back our wants, which are too easily/often confused with needs. And why risk losing a Main Street-designated downtown? More housing? There are only 2,000 more people in all of SLO County since the last census. We need to better manage the housing that we have, and increase it gradually, and not in suburban-type developments.
As director of the Greener Pastures Institute, I once came across a nationwide study that showed that new development, especially housing tracts, hardly ever ends up being a net revenue gain for municipalities.
Obviously, some are trying to draw a line in the sand. The biggest urban areas like Los Angeles and Phoenix gave up years ago on controlling sprawl and growth. Yes, it can happen here.
William L. Seavey