I guess it's a bit hard to define what a "dark age" is. But here are some examples:
1. When you lost interest in a certain type/genre/console of gaming.
2. When you couldn't find enough things to play, or, just wasn't sure what you wanted to play.
3. When you actually stopped gaming, or gamed much less than you used to.
For me it never got as bad as #3, but for me the sixth generation (circa 2001-2006) was a weird time in my gaming life. That period seemed like a blur when I think back about it.
It started with the death of the Dreamcast and the "demise" of my favorite publisher, Sega.
And 2001 was also a rough year for me personally, I had both family and financial hardships.
It's not like I stopped gaming completely....in 2001 I played a ton of PSO, but as 2002 started and the Dreamcast faded away, so did most of my
gaming time spent on consoles.
I picked up a GBA for Advance Wars, but it didn't hold my interest for long.
Got an XBox, but I wasn't a huge Halo fan, so I mainly used it to play more PSO and CapcomVsSNK2 online.
Then also got a Gamecube around 2003, really enjoyed it at first, but then also lost interest quickly.
And yes, I also got a PS2 eventually, but barely touched it, not being a JRPG fan and very little interest in what the PS2 had at the time.
The fact that Capcom went into a weird experimental phase and we didn't get a new RE game for a few years also didn't help.
When I think back I spent most of those years playing Starcraft on PC, and really started to get into emulation. I even bought an Astro City and started collecting arcade PCBs.
Anyway, I don't think I got back into "regular" gaming until 2007 or so, when the 360 was launched and I dived right back into fulltime console gaming.