Steampunk obviously grew from roots in science fiction, from the proto-Steampunk of Verne and Wells to the early authors in the genre such as Gibson, Moorcock, and Powers. Still, despite the gee-whiz gadgets and science fiction tropes of the unintended consequences of technology for which Man is Not Ready, much of the genre - particularly of late - is not SF in important dimensions. Boneshaker is an adventure tale; Soulless is a romance. Steampunk is a Big Tent genre.
Still, one must acknowledge Steampunk's SF roots. And if Steampunk is rooted in the Victorian era, one can wonder how such a world would develop - not 50 or 100 years afterward, as in Moorcock's Warlord of the Air, but half a millennium or more.
Alpha et Omega is such a vision, albeit a limited one. Shimmering columns, floating platforms, powered by mysterious bursts of energy - with gears and brass fixtures acknowledging a steamy past.