With digital, I see it more like the source is changing, not the entire system. LPs were replaced by CDs. CDs are now being augmented or replaced by downloads and streaming sources, for which we now use "network" players. In fact, that is my next move here in my main system--I'll still keep my current player around, but the next digital change I make will be for a network streamer/DAC that will handle everything.@Wildcat, Isn’t that gap being filled by great sounding digital?
Aside from that, the basics will always remain--we will always need amplifier, control center (preamp) and speakers to hear it all properly. It's true that there are a lot of ways to get music into places easier than we ever have before (think powered speakers and such, along with headphone systems). But those are also not primary systems for many of us here. I'm only thinking of this from the standpoint of someone in our "hobby" who is looking at a primary system for the bulk of their serious listening.
For the average homeowner/music listener, they went from hi-fi consoles in the 50s, 60s and 70s, to separate components in the 70s and 80s (receivers, speakers, and source), and in the mid 90s we started seeing them go into those plasticky all-in-one systems that were really nothing more than glorified, flashy boomboxes. Some of the recent streaming powered speakers out there are getting good enough to provide full range sound (like the RIVA Festival), and easy enough to operate through even the most basic of smartphones.