Part of it is the need in finding inks with true neutrality of grays and blacks.
Well, I'd say "desirable hue" instead of 'neutrality'. Silver gel paper is often not really neutral, and vice versa, my inkjet prints are not necessarily less neutral unless I deliberately add toning. Yet, how the hues shift as we travel through the tonal scale is definitely a factor that allows for enormous variation. In addition, given that perfectly dead-neutral grey probably doesn't exist in either domain, the question remains which inks produce hues that are desirable, and/or can be used to mix desirable hues.
Then there's media type; of course there's baryta paper for inkjet, but I think anyone who has used it as well as darkroom FB/baryta paper knows that there are subtle or sometimes quite dramatic differences. Yes, inkjet baryta undoubtedly shows similarity to FB silver gel papers, but it's really not quite the same. And there are indeed differences between them. Coincidentally, this makes inkjet baryta printing fairly costly since these papers for the most part do not come cheap. Moreover, in the testing I've done, the differences between inkjet RC papers are very slim (other than paper weight/thickness), so I found relatively little advantage to very expensive inkjet RC papers. On the other hand, the more expensive baryta inkjet papers really are significantly nicer (and thus, different) from the lower-end ones. But the price differences is also dramatic!
These are just the material choices; the question of how to go from a monochrome digital image to a tangible inkjet print and all the tonal corrections and toning options involved - I think that's where the real challenge is. And it's every bit as big a challenge as managing these aspects in the darkroom, IMO.