Yes, a tremendous amount of R&D has recently gone into improving inkjet technology, but there is also a fair amount of "good enough" plateauing at this point, requisite to turning a substantial profit on the extant versions of it, and recouping all the underlying R&D expense.
Things will keep on incrementally advancing; but anything really ahead of the pack would undermine what they're already doing. And let's face it, those inks and receiver papers have a horrendous profit margin built in, especially cumulatively, by the time they reach the retail level. Chromogenic RA4 color papers are a bargain by comparison, even with the chemistry factored in.
But at the same time, chromogenic printing has greatly improved due to its own ongoing evolution, especially with respect to permanence issues. And now people are able to apply advanced controls to that via PS etc just like they can for inkjet, although I personally prefer the all-optical true darkroom pathway. There's nothing better than real home cooking, although it's simply too slow for typical commercial operations.
Safety-wise and enviro disposal issues, per commercial applications, RA4 is a minor problem compared to when the T. Rex of Cibachrome stalked the earth. And all the pro lab output even then was flea-sized compared to what the military bases, shipping ports, paint factories, and oil refineries were doing around here. Now a major polluter is ironically the electronics tech industry itself, along with the pharmaceutical plants. Yeah, those places can be very safe inside, worker-wise, but their effluent going out is a different story, not to mention all the e-waste being generated as devices go obsolete at an absurdly rapid pace.