My personal take on touring vs bikepacking is that the bikepacking movement was always more parallel to touring, rather than a superset. The bikepackers I've met are usually a lot more focused on minimizing the amount of stuff they carry.
It can be simplified into a "saddle bag" vs "paniers", but IMO this is just a symptom. A form folows function. If You need to carry a full tent, sleeping bag and a change of clothes, touring paniers and heavy frame are probably the only way to go.
If You can cut down on comfort (or are optimizing for speed over long distance), suddenly You're left with a whole lot of options on how to carry whatever's left and You can use much lighter frame to do so.
Touring is from French. Means to go around and about. "Tour" is short for "Tour a velo", which is to travel on a bike. It encompasses short & long trips.
Touring vs bikepacking being distinct I think is an anglicism, an americanization and a commercialization of the terms. The Americanization part I believe is "Bike Tour" being mistaken for in-contrast to "Car Tourist". "Bike tour" has nothing to do with "Car Tourism" or "Bike tourist". It is not short for 'tourist', which is where the americanization comes in. The etymology is French.
Take a look at my counter-example - was that a tour, or a bikepacking? It was 50% pavement. Meanwhile 300 miles was on one of the worlds most famous bikepacking route. These distinctions based on how minimalist of what you carry or where you go make no sense. Given that example, the most consistent answer is clearly "both". It was a bikepacking trip - I was carrying what I would have were I backpacking, while on a bike. Because all bikepacking is touring, it was therefore also a tour. Had I stayed in hotels/hostels and/or with & friends every night (not carrying everything I needed), then it would have been touring and not bikepacking.
We can look to the etymology of the words. 'tour' comes from French. You can do a "tour a pied" (on foot), "tour a velo" (by bike), or "tour a voiture" (by car). Because cycling is the national sport of France, "un tour" is understood to often be by bike, it's just shortened. Bike tour comes from that etymology, it is a superset. A bike tour might include a 'backpack' (bags), or it may not.
Language does evolve. The "current" anglicized understanding is silly though and contradictory. It's also way more commercial than I'd like.
Sorry.. I once spent a solid 7 hours thinking about the difference of touring vs bikepacking while on a bikepacking race. I had some time to really dig into it... I kinda dislike that 'bikepacking' is thought to be something apart from touring (and only in mountains, only on dirt, only with inline bags)- when instead bikepacking is just a subset of bike travel, bike touring.
It can be simplified into a "saddle bag" vs "paniers", but IMO this is just a symptom. A form folows function. If You need to carry a full tent, sleeping bag and a change of clothes, touring paniers and heavy frame are probably the only way to go.
If You can cut down on comfort (or are optimizing for speed over long distance), suddenly You're left with a whole lot of options on how to carry whatever's left and You can use much lighter frame to do so.