I don't care who wins console wars, but I want to add something about last generation regarding PS3 and 360, which extends to this generation with Xbox vs. PS4.
The sales numbers were virtually identical by the end of the generation, maybe one or the other "won" by a few thousand units. But, sales numbers early in a generation are more valuable than sales late in a generation because they lead to higher licensing, fees, and extras profits throughout the generation. If one console has a many-millions lead for several years, that is several years of exclusive sales and fees earned by that manufacturer on 3rd party software, accessories, and service fees.
3rd party licensing fees change per publisher, but generally, somewhere around 20% of the profit from a game goes to the console manufacturer. If one console exclusively dominates the industry for 2 or 3 years, then they're reaping large 3rd party licensing fees on third-party games sold for those years. As the generation lingers on, and console sales even out, the split of profit from 3rd party software sales evens out but that initial head start usually doesn't even out even while the number of units does.
Like Microsoft in the last generation, Sony jumped out to a big lead, and sold far more 3rd party software over those years than Microsoft did. Even if the numbers even out this generation, which they likely won't, Microsoft is going to have 2-3 years of miss revenue.
Beyond things like 3rd party software profits, there are also other residual costs like online fees. If you bought a 360 early in the last generation, it's likely that you also paid $50/year for Xbox Live at least for those first few years. Maybe if you bought a PS3 later you canceled Xbox Live (although maybe not, Xbox Live was leagues better than PSN last generation). Likewise, the console that you first buy in this generation is more likely to be the console that you stick to that ecosystem for, and you're less likely to pay for two online service subscriptions. Sony's early sales this generation will lock many gamers into their ecosystem, even if they end up purchasing both consoles in the end and the hardware numbers even out (which they probably won't).
There are other factors that go into why early sales are better than late sales as well, largely around recouping sunk costs earlier in a generation and being able to reclaim lost cash. So, last gen, 80m vs 80m is an argument that only matters to fanboys.
