The TS-890 is not an SDR. Kenwood is not pushing the state of the art, not investing in SDR
Really? When you say SDR, that means a lot of things. The receiver chain in the Kenwood is dual conversion superhet, 2nd IF is DSP. If by SDR you mean Direct Digital Sampling, then no, the Kenwood is not that. At this time, no Direct Digital Sampling radio can handle the signal levels that the TS-890S controlled high level mixer can, they will simply fold because A/D technology is just not there yet.
Kenwood pushed the state of the art in Analog technology and did a great job, the only other receiver that can come close to it's mixer performance is the Yaesu FTdx 101D, which also uses a high level analog mixer front end.
Sorry premature funeral committee, but Kenwood is still in business until Haruo Kawahara says it's not. Why don't you stop telling him how to run his business, give him time to do it his way. Be patient, it takes time to push the state of the art. They will build a Kenwood ham radio Death Star, that will shut the premature funeral committee up good.
Consider yourself lucky if Kawahara doesn't show up here very soon to threaten and chastize you severely.