The couple things lacking on K are pretty huge, but people really underestimate how much goes into DIY media servers and the many many risks inherent with them.
The whole process relies on coders and companies with far more spotty and unstable history than K. It relies on defeating copy protection schema that have and will change again. AACS 2.1 almost took down the hobby. It assumes disc releases will be plentiful in the future (less and less likely, K already has 250+ more movies in 4k than on disc). Then add up the hours spent ripping, more so if you do MKV, and I still content at least half the people here and other places making MKVs are missing proper forced subtitles in some portion of their rips and making other mistakes. Don't want to do MKV and want to rip full ISO to ensure proper content? Well, not many playback options (Russian/Asian jailbroken firmware on a now out of production Oppo navigating with a kludgy/ugly network browser is your best bet). Most of the setup us DIYers have too would never be maintainable and in some cases even usable by our families. That said, sometimes it's fun tinkering, but sometimes it's really a pain.
K delivers (sans some specific audio codecs on some releases) all that quality without all that risk and work, but it costs. Hopefully it will cost a lot less with MA.
Every time I get a disc, rip a disc, or jump through extra steps to get a ripped movie playing on my theater during a movie night, I keep asking myself WTF am I doing. Just pay the money, get the movie on K, press 2 buttons to download it, and 2 buttons to play it and make your life simple.
For audioguy as well, in the latest kOS, you can set the movie wall to a static alphabetical order. It's an option. So no more shuffling. Similar navigation, but movies are shown in a fixed order up and down and left to right.
That said, if I added up all my hours and dollars spent ripping, tinkering, maintaining, changing, and so on over the years, I would have more than enough money to add a 40TB Terra to my Strato without question. Plus who really, truly wants to buy, keep, and even bother handling physical media nowadays when we have options like K.
I look at Google Stadia coming for games too and really question my building custom PCs for gaming when for $10/month, I'll have 4k/60 gaming at my fingertips on any screen and no effort. Parallel ideas there, but at least a gaming PC once built and running is an integrated system with legit storefronts and so on.
I'm assuming the studio mentioned for 8/28 is MGM as well. With potential for lots more UHD content, that means we could see the whole gamut of Bond films and such. That would be amazing on K (given the entire collection is 4K on iTunes and the latest films are slated for UHD disc now).
Building on some earlier points too, K did what feels like a lot in 2018 and early 2019. There was a ton of growth in the store in that time from major studios to massive amounts of 4K/HDR stuff. The last several months have added only a little thought at nowhere near the same pace. In the meantime, we have major omissions that owners are demanding, so the silence really unnerves people. Again, I'm still holding out a lot of hope (ideally not too much) for CEDIA and big things very soon.
My gut tells me K is still the best long term option to compliment an Apple TV for content ownership and viewing in a high end system, and that going with K will pay off in the long run when the DIY scene inevitably hits one or more roadblocks. I would love to see, but don't really expect Apple or others to jump bitrates by 2-3x and add lossless audio any time soon, so K is it.
K really too has so much potential. There's so much they can do in software features and future hardware if they have the vision and make the investment to bring it to us.
Video: JVC NX7, Stewart Cima Neve 135"
Audio: Marantz AV7704, Emotiva XPA-11 Gen 3
Speakers: Focal Electra 1038 Be x 2, Electra CC 1008 Be, Aria 906 x 8, REL S5 SHO x 2
Sources: Apple TV 4k, Kaleidescape Strato, Oppo 203, Xbox One X, Nintendo Switch
Xbox Live: TrackZ