Claremont did it--iconically, successfully, and with ease--for nearly two decades.
That's your opinion, to which you are certainly entitled. However, to counter your argument with actual facts, I'm going to skim through Bendis' run and see just how much more time and focus were dedicated to Jean because, frankly, you are overblowing just how much of either Bendis committed to her.
I should say the same to you: You don't have to justify why Hickman failed to focus on other characters outside of a select few or, more importantly, why he was unwilling or incapable of either reigning in his writing team or adapting to their changes and preferences in order to tell a more fluid and cohesive story that didn't require nearly two years of waiting for a four-issue miniseries.
There are myriad ways he could've told his story and more effectively. A story, mind you, he seems to have had neither the control nor wherewithal to bring to a conclusion until now. Everything he's doing in Inferno who could have spread out through X-Men and/or other books for the two years he was "Head of X."
I can tell two things right now: 1) We are debating different things and 2) it bothers you when someone criticizes Hickman. You're focused on specific characters, blaming writers to defend him, and totally disregarding my opinion and superimposing your own over mine despite the fact that I've been transparent with how I feel. I've already made it clear--repeatedly--that my criticisms of Hickman's writing are not centered on how he handled Jean but, rather, how he handled the entire franchise, so I'm not sure if you're dense or purposefully attacking the straw man. As for being angry, what's starting to piss me off is you telling me how it is that I feel and what my criticisms are based on. Please, don't be so presumptuous.
Oh, please. Big deal. He Eternal-ized mutants, threw in a dash of House of Cards, and plopped them on an island. Groundbreaking. Actually, to contradict my sarcastic irreverence, it was and is sort of groundbreaking and certainly injected much-need life and novelty into the franchise. However, blaming all of the writers and predicting that they will fail without Hickman just to defend him is not a good look and screams of fanaticism over one writer. Mind you, there's nothing wrong with being a big fan of a writer, but let's call a spade a spade.
That being said, let's make something else clear: The X-Men were around and highly successful before any of the current writers, including Hickman, had careers. Moreover, the X-Men will be around long after these writers have moved on and been forgotten.
Duggan isn't responsible for the entire X-franchise. Furthermore, he was charged with writing and introducing the new team while sandwiched in between multiple major events. Even still, he has made Jean, Synch, Polaris, and Sunfire shine while introducing a handful of fascinating plot threads and adversaries, and he's only on issue #5. We'll all be able to better assess how well he's done by issue #12.
Jean was one of the first three mutants to be classified as an Omega Level mutant and was referred to as such many more times than whomever your "everyone" refers to. Check it.
Yes, here we are, in a debate in which you insist on using straw man tactics to undermine my criticisms. Please do continue minimizing my opinion and criticisms by accusing me of just being "angry about Jean," lol. Jesus. Just so you know, in case you weren't aware, I've actually debated fans on this thread and defended the moments Hickman has given Jean.
He "gave them all the space they needed" and still went almost nowhere with X-Men, which, again, many fans have noted.
I'm going to need you to quote where I "blam[ed] him for a character he didn't write" because you keep relying on the same straw man argument to discredit my opinion. To be clear, I feel Jean was one of the luckier characters during Hickman's run. She had stellar moments under Hickman, Percy, and Duggan, who is writing her beautifully again as we speak. I am not bothered by her treatment over the last couple of years because, prior to this era, she had an amazing six-year run and, during this era, she has was singled out by Hickman to be the first to go against the Krakoan government and found the new X-Men.
Because he can't handle a large cast of characters, that's why. As you yourself noted, he's a concept, world-building writer. His scope is limited. For example, Claremont could do both and with more heart.