The key is, like any other investments, is diversification. San Diego a long time ago diversified well out of the norm of just tourism and just military/defense. If you look at SD, SD doesn’t have one thing they are exceptionally known for, but there’s a lot of things going on. High tech, bio-tech, tourism, military/defense, very large healthcare research, university ( UCSD is a top rank school). Any sort of hit in any one sector (tourism) is blunted by the other ones. Heavy concentrated LV or Bay Area is great when times are good, not so great when growth and speculation comes to a grinding halt. Everyone knows that. Just look at history.
While a one time, exceptional event like a pandemic probably cannot be predicted, the economic fallout is probably is much more so.