True, but the CX5 was designed to compete with things like a Commodore-64. In a doomsday scenario, there wouldn't be "other" computers as we know them...if Yamaha wanted to sell Cubase, they'd say screw it, let's just make a computer. That's what pretty much what all companies are doing for instruments, with embedded systems.
Also remember that back in the days of CX5, it was far more difficult to assemble your own computer. Today, making a PC isn't much more difficult than it was to assemble a model airplane.:) Yamaha doing a computer would be similar to Sweetwater doing Creation Stations.
I was thinking of the Yamaha computer that was a Windows laptop with built-in MIDI IN and OUT ports, but I can't remember the model.
After a VIC-20, I assembled my first PC from a kit of parts from my local computer store. They assembled and sold standard and custom configurations, and the kit was a couple of hundred bucks cheaper than one ready to go. With two floppy disks (back then a 10 MB hard drive cost about $500), 256k memory, and a Hercules monochrome graphics card, it cost me about $700. It was the most expensive computer I've ever bought. I think that would have been around 1984.
But the thing that concerns me is that I believe in the importance of local storage. I would assume the odds are remote of iCloud or OneDrive becoming victims of ransomware...but again, thinking the unthinkable...what if one day, the Kings of Ransomware tell Amazon "$100 billion to get your servers back?"
A more plausible scenario would be simply that the cloud company you chose for your data (and applications, if you dared) just decided one day that they didn't have any more money, turned off the power, and walked out the door. It could even happen to Google some day.
We have Chromebooks now, that mostly run applications out of the cloud. They seem to work pretty well for schools - they're cheap and it's a good way to control what software the students use (and can't, at least not in class). Is there a DAW for the Chromebook? There's a class of computers now called "thin client" that have just about enough memory to run a basic operating system and seem to be getting some traction as a gaming computer. I have one running Windows 98SE and the Audio Precision 1 software (no cloud involved with that). I bought it for $50 from an eBay dealer. But with this approach you might have to buy one computer to run Pro Tools and a different one to run Cubase.