I view the killing of physical game media as having two aspects that, while intertwined, are separate in some ways.
The first is the loss of the physical item. I like organizing carts and discs, looking at them on my shelves, reminiscing, easily putting one in a console to replay. Same with other media for me: I buy books, only read physical ones. I listen to digital music (generally downloaded from sites like Bandcamp) but for albums and artists I like the most I buy vinyl. I get that this isn't a big deal for most people, but it is something that is permanently lost when you get rid of physical media.
The second aspect is control and ownership. This is indeed intertwined with the physical aspect, since you can do things like resell a cartridge or disc and let someone easily borrow it. But control is possible with purely digital games, they just need to not be locked down with DRM. And companies like Sony want to kill physical games because it allows them to keep those DRM locks on digital-only copies so you cannot resell your games, which is connected to the second point, control.
I also agree that the issue of control is more important. How do we continue to make sure our games, that we bought, aren't just taken away from us? What happens if you lose your account with Sony/MS/Nintendo? What happens if your old console that you downloaded a game on breaks? The death of physical games is also a step on the way to subscription-only services, where you won't even be able to play something unless you are actively giving money to a company regardless of how much you gave them before.
The ways forward that I see are legislation that would do things like force companies to allow people to always download games they bought in perpetuity, regardless of account status, and if the company dies the successor company must do the same or release the game into the public domain. But given the power of large corporations and current intellectual property laws, this isn't happening anytime soon.
Practically, then, the only way I see is to either have a console that is hacked in some way, or only play games on an open platform like PC. And there you can only buy DRM-free games or, at worse, if you lose access to game in some service (e.g., Steam) you can still pirate it (which I'd feel morally fine doing if I bought it already of course, but that does bring legal risks depending on where you live).
And the later option still doesn't address the larger issue of preservation, as the OP's blog post notes: games will be made for locked-down consoles in the future and will be lost forever unless the hardware is hacked or a law demands the game's preservation.