It seems to be an issue only in that people seem to want in a certain place but not pay the prevailing rent to do so. If they're willing to pay the prevailing rent, there is no issue.
In a neighborhood like mine (75% SFR, 25% MFR free-standing homes in West Cambridge), you can bet that I'll object to zoning changes that would allow "just building up". I don't need the noise, traffic, additional pressures on the school system, nor do I want to live in a mid-rise and high-rise district. If I did, I'd have bought in one...