Year 1: Focus on establishing your market, reach 5-10 million consumers, most games still crossgen.
Year 2: Market growth continues, releases for last gen begin to slow, crossgen titles almost nonexistent, price drop of $50 for the PS4, $100 for the Xbox One for the holidays.
Year 3: Developers begin to get comfortable with the systems, learning better tricks. Games that truly tap into the PS4/XBone's abilities become more common. At this point all PR bullshit has faded and gamers know what to expect from the gen as a whole. Rumors of new SKUs start to pop up.
Year 4: PS4/XBone become the primary systems on the market as support for the PS360 consoles stop almost entirely. New SKUs debut, a "sleek" PS4 and an "upgraded" XBone are released. (By this time the next Nintendo system may well be out. Hopefully it'll be more powerful than the PS4 and XBone, but more than likely nowhere near as powerful as what the PS5 will be later.)
Year 5: Business as usual, games games games.
Year 6: Announce new systems at the top of the year, release them near the end or the start of the seventh year.
Something like that.