How can you know that? All my current digital downloads are still available to re-download now, so why wouldn't they still be available later on?
Are they? You must not own anything on the following platforms: Playstation Vita, Wii, DSi, Wii U/3DS, and more.
The reason they may or may not be available later on is that financial conditions and incentives change - at any time these companies could suddenly close or revoke access to your digital redownloads. It's fine that you're willing to place your ability to play these games in the future in the hands of these third parties - but in most cases I'm simply not willing to do that and therefore I prefer a product that remains both accessible and under my proper ownership without a requirement of a third party's efforts.
You are right that I should not have been so definitive - but in general and on the long time frame, these items will not likely be available readily. History continues to prove this as time marches forward. Some may have a longer duration than others in terms of availability, there's no doubt. I think cases such as the 360 availability of digital items are the exception rather than the rule.
And sure, you can technically play a few BR disc games from scratch, but a very high percentage of them either won't run without an update, or run like shit due to so many devs releasing unfinished games.
I don't believe it's "a high percentage". It may be a significant percentage these days - but many games work perfectly fine off of the disc without internet connectivity. This is often overstated.
Way I see it? If BR discs are "fine" then so are GKC games.
They function completely differently.
Personally speaking, I too would prefer getting all my games complete on Switch carts,
Yes, I often buy specifically for Switch just because of this fact. I completely agree - it strongly affects my purchasing preferences.
but I still have to suffer shitty BR discs that will rot in the future,
I have Sega CD discs that are fine. Disc rot is overstated, I've only directly observed it on mistreated discs. Keep your discs in proper climate and storage and they will last your entire life, possibly to your descendants.
need high data patches, or simply won't run well with a base version, and I'll still have to suffer big downloads for GKC games, but it is what it is and I suspect it'll stay that way until it gets worse, ie only a completely digital or streaming option.
It will get worse, you're right about that. I can still hate it and resist it every step of the way, no matter how futile.