This OP puzzled me since I fly through SFO regularly and, though I'm GE, have never noticed extraordinary crowds such as those described. So I checked the CPB Wait Times website https://awt.cbp.gov
And I see that indeed on April 9, between 1 pm and 6 pm the max wait times (for non citizens) were between 220 and 165 minutes. At 3 pm, it was 218 minutes.
However, that's between twice and four times the normal wait times for non citizens. Not sure what created this anomaly - an extraordinary number of international arrivals, lack of CPB personnel, IT problems, or a combination of these - but it is not a regular occurrence.
I was once hung up in a mob at JFK for two hours (pre-GE) because they were unable to machine read the passports. When I finally got through the CPB officer told me the rule was "No swipe, no go." Even though only two years before, they weren't machine reading passports at all and they still could have done the job without it.