You have mischaracterized the motivation of most homeowners. Have you ever actually talked to many? The loudest, most influential NIMBYs have lived in the area since before the first Internet boom and plan to die in their current homes. They don't care about housing as in investment, and in fact complain about rising real estate values because it drives up their property taxes (albeit slowly due to Proposition 13).
What they actually care about is quality of life. Their perception is that higher residential density means more traffic, parking issues, noise, crime, pollution, school overcrowding, etc. If you want to get them on board with higher density then you'll have to find a win/win solution which addresses their concerns. Maligning their motives will accomplish nothing.