I'm heavily into retro computing, and my cut off year is 2000. Anything newer than that is not 'retro' in my book. For vintage computing though, I think it would be before the IBM PC, so 1981.
However for consoles 2000 slices between machines of the same generation like the aforementioned Dreamcast (pre-2000) and Gamecube (post-2000). These are systems that shared groundbreaking titles between them like Phantasy Star Online; which was one of the very first online multiplayer games for consoles (and which I still play weekly guild matches, streamed on Twitch).
After that generation of consoles the specifications for consoles were all pretty similar to PC (chipsets aside): ethernet, wireless, HDMI (the previous generation were all pre-HD too), a HDD, etc. But it was the Dreamcast (and, released much later, the Xbox) in the generation of consoles before that really pioneered this shift in paradigm for console gaming and which many of the consoles of that era only had support for via addons (GC Ethernet Adapter, PS2 Network Adaptor, HDDs for the PS2 Expansion Bay, etc. Heck, even the GC didn't ship with ethernet instead having a dial up modem, and it wasn't even as fast as 56K in most regions!)
Thus I think they deserve to be retro for the same reason that 1996-2000 for PC gaming does: they defined how the next couple of decades of gaming would look while making plenty of mistakes along the way.
They definitely lost innovation. The only innovations in gamimg were bloat and greed. That's why is more entertaining to play older titles: they are all about play, they do not try to extort you or bring your PC to the limit.
Take Untitled Goose Game, for example. It was released 3 years ago and you play the part of a Goose who's mission it is to annoy as many people in a quaint English village as possible. The game is basically a modern day equivalent of the How to Be a Complete Bastard class of games from the Spectrum era of home systems. And it's fun too!
There's also no shortage of modern games released for older hardware. On the shelf behind me I have at least 5 games released in the last 5 years for various Sega consoles. The Gameboy and Gameboy Advance also see a surprising number of new releases each year too (though I don't collect for those consoles specifically).
I'm sure John Carmack still does amazing tricks at Oculus.
The Dreamcast had a built in modem and some models of PS2 had one built in.
Yeah that's what I meant (GC and DC too similar acronyms -- easy to typo). I did say elsewhere that the GC's online capabilities required an addon whereas the DC shipped with one).
That said, there were a few special edition Dreamcasts that shipped with the ethernet adapter instead of a modem. They weren't common but they did exist.
I've got a GC and DC sat next to me too -- unfortunately neither with an ethernet adapter. I do have a DreamPi hooked up on the DC though.
> there was only 4 games in its entire library that could even go online.
5 actually, though the 5th only went online for DLC. That said, you can argue that it's a bit of a stretch to call PSO and PSO+ different games.
It's also worth noting that there were a few other GC games that supported the ethernet addapter too albeit for LAN play rather than online. This was in addition to those games also supporting crossover cable.
> and some models of PS2 had one built in.
The original models didn't have it. It was only the slimline models that had ethernet and they were released quite late in the life of the PS2. The previous models required a hardware expansion adapter to provide online functionality (like the GC). Sony were pretty late to the game in that regard because Sega and Microsoft had already proven online gaming by that point.
I believe there was a modem adapter for the PS2 too, but I don't know much about that.