Everything you say is correct and I understand your point of View .I haven't listened to any of the videos yet but will do so later this morning. Interesting reading these comments here.
Off the top this would seem a hard sell for me personally. Not enough to move away from my FR-8X. I purchased it in 2015 and it's been solid for the past decade with literally hundreds of hours of playing it.
I think I use my FR-8X in a different manner than most, however. I use predominantly a jazz bassoon register I customized to my taste, a string bass with organ chord, and a Master Accordion register occasionally. The main draw for me is light weight, ability to use headphones for practice, and much less effort on bellow push and pull. For that, it's been wonderful.
I used all of the orchestral sounds and drums for probably the first year but felt they didn't add anything to my playing.
At $8K US that's around $8700 US with taxes and shipping. Even if the selling price is below the MAP and the total is $8000 US that's really steep for a digital accordion.
I bought my Yamaha Montage M8x last January and it is their State of the Art flagship workstation. It is just amazing. I think it was $5K shipped to my door and I play it daily and love it. It feels like a piano and I'll never begin to approach using 10% of the things you can do with it.
As a humorous aside, I agree with the comments about the "aging" parameter and all the BS additions to make it sound like an old acoustic accordion. The M8x has hundreds of sounds with intentional pops and clicks to simulate vinyl records or old time pianos. You can eliminate these "features" and with 4000 sounds they get lost in the mix, but there' a subset of users out there that really enjoys this. I'm not sure why.
I take it with a grain of salt whoever sponsors whatever accordion. I recall Frank Marocco and Petosa and they still use his "the best accordion I have ever played" on their website. Then he was all Victoria. And he was FR-8X for a short bit. But on a lot of his albums he always played his Giuletti. Dick Contino was Petosa, and Cordovox back in the day. Art Van Damme was Excelsior. But I think they all follow the money and who knows what they truly think. Since they are the top of the top my personal feeling is it doesn't matter what they play because they are so talented. The minions (rest of us) hear them play that particular instrument and think, hey, that sounds great. I should get one too. It's neither here nor there. That's why I tend to value YouTube reviews of peasants like myself playing an instrument and providing their thoughts.
And I'm not a hypocrite. If Korg dropped a Fisa off on my doorstep and told me it's free for a sponsorship, this would be my 100th post in this forum on how incredible the instrument is!
The montage is a wonderful top of the range Yamaha workstation . I think that you could even midi it up to your Roland FR-8X WOW that would be one heck of a sound ...unbeatable !!!
Over the years I met Dick Contino several times and we used to meet up at the Vegas Convention ......He never really liked the Cordovox as he used to travel all over the states and he found it some what troublesome and prone to being unreliable ......mainly due to all the travelling and Vibration it was subject to. He said America is a vast Country with a lot of no where in between and trying to find anyone who understood the Cordovox virtually impossible ........He never wanted to be called Mr Cordovox !! and preferred to play his Petosa by god that instrument took some playing punishment from his style of playing ........but it would always work !!