If I heard right, it's not enough that the vaccine could be 90% effective...it matters 'how many people actually get vaccinated'. The medical community would like to see something on the order of at least 60-70% of the population inoculated, however, right now that seems to be the percentage of Americans who DON'T want to get vaccinated. Additionally, there needs to be a well-functioning test/contact tracing system in place.
btw...for comparison, the Measles Vaccine is 99% effective and a sufficient percentage of the population gets inoculated, so even though it has a "Contagion Factor ('R-naught)" on the order of 18 (very high) we are all able to go about our normal lives. COVID-19 has R0 factor near 5.7, I believe, so if we work hard at mitigation and all get the vaccine, we'll get through this.
Given the circumstances, Fauci is being the outstanding medical professional and saying what needs to be said...not just what the "patient" wants to hear.
Things are going to get better...let's just trust in the Rx...mitigate, get the vaccine and tell all your family and friends to do the same.