There must have been a secret handshake job done between billet box and sxk or the other manufacturers wouldn't be doing variations on a theme but actually cross compatible stuff as I know all the Chinese vendors are well aware of the current resurrected bb craze.
I completely get pods. I do wish more where cross compatible coil wise and had room for an rba and I understand the bb thing is based more in the top end collectable hobby side of vaping but for modern device's, once it's past a certain size then a mod and tank has to be preferable.
I'd say the best way to go for aio design's would be to revisit the exvo stick / stig helix style. Tesla made some usefull ones but soon I reckon we'll see more.
I did see coppervape where looking at 're releasing the stig clone so perhaps that what's next.