I'm going to go out on a limb here and suggest that NJ didn't see Raducanu's US Open triumph coming, nor for that matter Leylah Fernandez's own remarkable run on the other side of the draw, nor Swiatek's victory in the 2020 French Open, nor Krejcikova's the following year, etc etc.
Especially in the women's game, tennis is too unpredictable to be able to say with confidence who will succeed. We can perhaps have good ideas, eg amongst the current crop of under-18 players who have largely escaped notice, there are at least half a dozen exciting players from the Czech Republic alone, and a good handful more besides that are worth keeping an eye on. But in as much as I'll be able to predict which are successful, it's only because I can name so many that I'm bound to be right about at least one of them. But not by skill.
I'd expect, all the same, that it'll take another couple of years before Raducanu can seriously challenge at Slams again. But she's still young, she still has plenty of time, and I think she's got the drive to succeed that'll stand her in good stead and see her through this rotten run.