Sacramento is getting people's attention. Hopefully, things continue that way.
New construction is a whole different animal than buying existing properties that are already rented.
Even if demand is heading in the right direction, has it reached the tipping point, where we can expect lots of investor dollars funding many new multifamily developments? Sacramento may not be there quite yet. Maybe that's why you feel there aren't enough proposals right now.
The Sacramento market doesn't exist in a vacuum and investment dollars are not infinite (granted, the U.S. Federal Reserve Bank may disagree

).
Rents in the Bay Area are astronomical. So the lure of making ridiculous money in San Francisco may draw investment away from new developments that Sacramento could reasonably support now.
However, the cure for high prices is... high prices!
As the Bay Area starts pricing out certain segments of the market, people will look to Sacramento as a place to live. If enough people do that and they make enough $$, Sacramento may get those dense, urban developments we crave.
It's a process that we may just have to wait out.