Granted, there is a lot of bulk tobacco out there in the world, but if you are also limiting yourself to buying only bulk, you are limiting yourself to a lot of blends out there, that are only in tins and packages.
I wouldn’t limit yourself like this, there’s no real reason to do so, unless a specific blender was putting a lot of nasty artificial flavors and chemicals in the blend.
I see you’re in England, but if you were able to buy there. G.L. Pease blends, he doesn’t use PG, and possibly about as pure as you can buy, as a prepackaged blender.
Many of the highly acclaimed blenders around the world, selling their blends packaged, many of them are probably, possibly even better quality, compared to many of the bulk blends you are buying.
It’s also harder for vendors to maintain the stability/moisture of bulk blends, compared to a vacuum sealed tin. So when buying in bulk, there is also a good probability of getting tobacco that hasn’t been well preserved and drier.