I've been noticing (obviously purely anecdotal here), that those in circle of DM's have been including more and more science fiction elements in their otherwise Tolkien/medieval/high fantasy games. I have no issue with it and know the rich tradition of slipping sci-fi in at times, but specifically with my peers who run D&D 5e, they are heavily pursuing science fiction elements in their plotlines - Spelljammer space battles, creating pocket realms of mechanical societies with vanishing mysticism, and the like. I could totally be off-base here, but has anyone else noticed this drift or shift occurring and how do you feel about its increasing prevalence?
		
		
	 
I have not so much noticed a drift as a return.
A new D&D always starts from a pretty pure "Standard D&D Setting" point: faux-European, pseudo-medieval (basically "pop history"/"pop sociology" version of medieval Europe), schizotech (15th century armor and 12th century social structures and 17th century politics and 9th century castles, etc., but no 14th century gunpowder weapons), vaguely Tolkien-esque (lost glories in a fallen world, but elves aren't immortal, there is no big-G God, elves are just wistful Because, halflings exist Because), etc. That's pretty much always where things begin. Wiggle-room comes in how bright vs gritty it is, how much modern mores affect things (e.g. greater gender equality), accessibility of magic, etc.
It's natural to start off at this point because, any time you're working with a new system, you need to learn its ins and outs, and it's easier to do so if you have a familiar, comfortable context to see it play out within. For most folks, that "Standard D&D Setting" framework is precisely that. It is, for them, the closest thing to a white canvas. Or, perhaps, to white rice--a simple meal well-made, so to speak.
But white rice can become limiting, unless you start adding things to it. And that's where the sci-fi thing comes in. It 
necessarily stands out against the presumed "Standard D&D Setting" backdrop. You can't help but notice its effects.