I mean, I think at this stage in the game it'd be obvious that any comparisons being made have to be considered in the context of where the system is sitting two months from launch, compared to where other systems were sitting two months from launch.
I mean, the real problem we're going to have at the end of Gen 8 is that not only will the Wii audience have been largely absent, but a big chunk of the PS2 audience will as well. (Recall that Xbox 360 + PS3 was a few million north of PS2 + Xbox's audience, with most of the gains last gen coming from Wii's gains over GameCube. Gen 8 has absolutely no shot at surpassing Gen 7, but also probably won't even match Gen 6.)
We don't know for sure whether Gen 8 will be anywhere close to Gen 6 when it's all said and done. There's a very good chance that it won't, but if it does then it will probably be due to XB1 > XBX. This is a question that may not be answered for a very long time though, depending on how low the PS4's price ends up for sales in RotW. IIRC, the PS2 sold >50m after PS3 was released. I'm not saying the PS4 has potential to do that, but the upper limit of its potential seems to be a good amount in excess of 100m, and could see some level of success at a cheaper price point down the line. Time will tell, it could all collapse, I'm just not 100% sure that this gen will be smaller than Gen 6. Also why I was wondering if Switch will count for a Gen 9 that may not be started by other companies for another 2 or 3 years. I could see the Switch being another Wii/DS/PS2 type breakout, it's got the big differentiating feature, and all of the early hype behind it.