> If it’s as contagious as they say and spreads in asymptotic people then why wouldn’t there be a significant population that has acquired and recovered from this?

Because all the effects are limited by the time it takes for them to happen. We know the speed of growth, it's much faster than the expected recovery times. From all known COVID-19 cases the number of recovered are still dominated by the recovered in China.

   China: reported cases: 81,008
          dead:       3,255 
          recovered: 71,740

   Whole world: reported cases: 282,395
                dead:      11,822
                recovered: 93,189

Virus causing COVID-19 is "novel" meaning not existing among humans at all until a few months ago.