From my perspective, at least, synthpop has gone through four distinct (and fairly broad) stages since it's debut in the late 70s--not counting the very earliest years when it was still struggling to find a place. Certainly by the time The Human League released Dare in 1981, synthpop was mainstream successful (at least in Britain, with a slightly more subdued yet comparable reaction in America. In some other markets--notably Germany--it was even more mainstream successful.) Despite that, synthpop remained a somewhat "fringe" element of mainstream music; more influencing it than cranking out hit after hit in it's own right. In the US, we didn't yet use the label synthpop; I called this stuff New Wave and had to then qualify it as "synthesizer New Wave" to distinguish it from other proto-Alternative groups, like The Church, or The Alarm or REM, or pre-Joshua Tree U2, or whatever--which were also lumped into New Wave. This first phase--emergence--is characterized by steadily growing popularity and mainstreamization of synthpop type sounds and conventions, as well as a steadily higher peaking chart positions, and gradually more and more bands operating in the arena. However, it was still dominated by a mere handful of guys who were the "elder statesmen" if you will of synthpop--Depeche Mode, Erasure, Pet Shop Boys, OMD, etc. Near the end of the Emergence phase, a number of smaller "copy-cat" bands started putting out stuff too, to slightly lesser acclaim, but which had modest commercial success--guys like Anything Box, T-4-2, Cause & Effect, Seven Red Seven, Red Flag, Camouflage, etc.
Following the "synthpop crash" of the early 90s, major labels dropped most of their synthpop bands, with the exception of the very top tier folks--who even then saw a massive down-surge in popularity and sales. This is the period I call underground--a nascent Internet connected a few distributors like A Different Drum, who managed to gather synthpop from independent labels around the world, as well as release a few items itself as a label. In this phase, the so-called "elder statesmen" of the past either chugged along or released items that abandoned their synthpop sound. For a little while, some of the lower tier guys from the past became "elder statesmen" of this phase. By and large, the scene was very indie, fairly underground, online, and dominated by a handful of labels and their output. In the US in particular, A Different Drum as a label (not to mention as a store/distribution point) was an important leader, and whatever A Different Drum released was bound to get plenty of attention.
Some new rising stars from this era include De/Vision, Mesh, Iris, Cosmicity, and more. Eventually, as the Internet became itself more mainstream, and digital music distribution became more commonplace, synthpop emerged a bit from this underground obscurity and entered two new phases--which kind of overlap with each other. First, there's increasing diversification and independence of the modern synthpop scene. As it merges with other electronic genres, producing narrowly defined subgenres like futurepop (which later migrates into an even more synthpop like sound over time), electroclash, and more, a number of bands come to surprising prominence, and they are mostly new bands, unrelated to the earlier phases. There also comes to be a great proliferation of bands; right now (since this phase is still ongoing) we are really spoiled for choice when it comes to synthpop. There are tons of new guys to discover, and there's no longer any need to really dig back into 80s back catalogs to find nifty stuff to listen to.
Not that you wouldn't want to anyway for other reasons--but you don't have to. The other interesting phase that's also going on right now is the curious mainstream faddishness of overtly retro synthpop. Artists like Little Boots, La Roux, Owl City, Hurts, The Presets, and even Lady freakin' Gaga are all putting out mainstream hits that are quite clearly synthpop.
Wherever it goes from here, it seems unlikely that another descent into underground obscurity seems eminent. The mainstream faddishness may indeed prove to be a short-lived fad (or it may not; in many ways, synthpop sensibilities have so thoroughly infused pop music overall that at least one reviewer has claimed that it's already "won" and taken over the world permanently) but the very diverse and thriving not-quite-mainstream scene seems unlikely to go away soon.
But even so, there's a recognition amongst many of these artists that they're building on the groundwork laid in the 80s by synthpop pioneers, and it's not unusual for many of them to do cover versions (sometimes only live, as a tribute to the fans) of 80s synthpop favorites. Just recently, in fact, I picked up some Mark Oh' and The Flash remakes of some Visage classics (actually, I've had their "Fade to Grey" covers for some time, but I just got "The Damned Don't Cry." Vocals by Marcus Fellechner of Rename.) And while it's a really pretty cool cover, the original is still... well, it's the original. One of my favorite 80s synthpop songs of all time, in fact. It's haunting, melodic, and danceable; it's got everything you want a good synthpop song to do.