As a former Biden will win believer, I've been converted into a Warren will win believer. Obviously it's not certain, but I don't think it's very likely that he will come back, after being behind in the national polls. That was the only thing he had going for him, and the only reason I thought he would win.
I still wouldn't count him out. He's been very stable for a number of months now, even in the face of Warren's rise, which makes me believe his floor is rather high. If Warren slouches because Buttigieg denies her a win in one of the early primaries, it's highly possible in my mind that Biden would be the main beneficiary.
I wouldn't say Biden's been stable. He's been on a slow but steady decline while Warren's been on a slow but steady rise. But you're right that Biden shouldn't be counted out. A Warren win in IA, NH and NV with a strong Super Tuesday showing (including winning California) most likely means she wins the nomination. If someone denies her a win in an early state, the race will be tight.
I will say though that this feels different from 2016 in that there never really was a doubt that Hillary would lose, even when Sanders was rising in the polls. Warren's insurgence feels more threatening and real.
