I think the Spring 2021 start time is very realistic (although I'm not sure how subsequent seasons would be handled). While I think it would be okay to start by mid September based on the projections I've seen, it doesn't sound like those in charge think the same way. OU canceled all in person activities through July 31st. Other schools are almost certain to follow suit. Obviously if things were to die down to a very, very low number of cases by June, OU could potentially reconsider that decision. Assuming that decision stands, though,I don't see any way the season could start on time. Most coaches are saying they will need two months of preparation time before they could play the season. That would put Oklahoma's earliest start time in October. We'll just have to wait and see.
My advice to everyone is this: if you want any chance of there being college football this year, stay inside like you are supposed to. Trying to act tough or whatever by going out to and violating the stay at home order only increases the chances that the virus may linger, and, right or wrong, if the virus isn't basically gone by the end of summer, there seems to be very little chance of there being college football in 2020.