Blue Angel 6 was very lucky. I know they were flying slightly further apart than their usual 36" between aircraft but the only pilot looking forward was the flight leader in #1. That said, had he seen the drone, there wasn't:
1) time or room enough to take evasive action as a formation
2) time or room enough to take evasive action as single aircraft
Since all of the pilots are keying off of either #1 or, in the case of solos 5 and 6, slot plane #4, not one of the pilots other than the lead would have been able to see, warn of or avoid the drone. That could have resulted in at least one plane damaged with varying degrees of losses up to all six planes going down if the leader in plane #1 had hit the drone and been unable to maintain control. Had the planes gone down, being over a city at the time and even with the stay home order in effect, there still could have been civilian casualties as well as the chance of lost pilots since there really isn't room for a safe ejection from the delta formation