What is to become of Marantz Reference and HIFI as we know it

So I have been in a quiet morning for KI and Marantz as a brand for five months now.... The Marantz brand has been an American Icon in high-end audio and Saul Marantz might very well be the first “Audiophile” ever?

The Marantz brand has been with all of us for soooo very long! And in my family I’ll always remember the glowing blue of the hard earned family receiver...

When Saul knew his time was up and when he sold his company he made sure he had the assurance that someone would have/keep his vision and they sent him Ken Ishiwata, aka KI!
KI kept his end of the deal and more! KI has always had Saul Marantz in mind and his best interest at heart when guiding the Marantz companies References series.... And now sadly KI is gone, no longer with us. I always thought that somehow I would meet him at some trade show or something and shake his hand, thank him for all he did to make an impression on our hobby and in my life... Again sadly that never happened and as someone who loves HIFI I regret it.

But the larger question looms as what happens to Marantz high-end reference series/products now? They have been carefully guided by Saul Marantz and Ken Ishiwata for all these years! And there was no passing of the torch as there was between Saul and Ken...

I fear that the lone fighter for Marantz HIFI is gone now and it will not recover? I hope I am wrong and that someone in the Japan division will take it up but only time will tell...

Here is to you KI for keeping that flame alive all these years 
Apparently he parted with Marantz in May, 2019 over corporate issues. He planned to begin other projects but died November 25, 2019. The cause of death was not been much revealed, but Stereo Magazine in December, 2019, attributed it to an autoimmune disease. He was 72.
I hope marantz keeps going on the right direction. While I made other choices for 2ch components priced at their reference level, I use a marantz AVR for my reference home theater setup and am awaiting delivery of the new pm7000n super integrated to power my third music system, to replace a Bluesound Powernode 2. Marantz does a lot well. 
Was KI really that important to the sound?

The Marantz house sound as we know it and is loved by many IS KI! That sound is his signature and why he was involved in all those tweaks you spoke about.
I read a review a while back on the new KI Ruby equipment. In that review it said that he was not happy with the sound of them at all and he sent them back with the changes he wanted to the Japan team, to change them to get it right and to recapture the sound he was looking for.
The Japan team made the changes and sent the units back to Europe where KI lived and he was still not happy! So KI took those units and he himself made changes to them until he found that Marantz Reference sweet spot, that Marantz/KI house sound....
KI then sent them back with what he had done and the rest is history as the Ruby’s were very well received!
KI was, during his time at Marantz, as important as any head engineer or company owner. Marantz was all to happy to put him out there to promote the brand...
I've had Marantz gear that was superb, and some just OK, and some just awful within the same series.   Many years ago had an integrated amp, perhaps a PM500 if memory serves that was quite AOK and the matching tuner was awful.  Before that a 2245 receiver that was excellent as well as the associated add on quad component.  More recently had a $3500 Marantz CD player that was quite picky about what disks it would and would not play, and played none of them very well.  Replaced it with a Sony SA 5400 ES that I bought as a refurb from Sony for pennies on the dollar and about one tenth of what I had in the Marantz and it is much better, a former Class A Stereophile player.
Very sad to hear about KI passing. I have SA 10 CD player and has been the best unit I bought, sturdy, very nice sounding and hefty. Yes, their reference product is cut above similar priced units elsewhere.