Not sure why people are obsessed with Harris dropping out but not Booker, Steyer, Yang, Klobuchar, etc
Harris' campaign is clearly on a downward spiral, and is short enough on cash, that a cannier candidate would likely start to consider a tactical departure and immediate endorsement (likely of Warren, given their shared political history).
That's not to say that I don't want most of the candidates you mentioned to drop out. It's just that I think that if a candidate like Steyer is running a vanity campaign, it's a lot harder to get them to drop out, especially if they still have an effective funding apparatus.
Some candidates leave because of money, while others need to taste defeat in IA and NH before they drop out.
I think Harris could be persuaded by her aides to leave, in order to protect political capital, while candidates like Steyer, Yang and Gabbard will need to be resoundly defeated in order to make them consider leaving the race.