If, as so many people like to say on here, that 90% of Nviida's profits in the video card segment come from selling to the professional market (i.e. their Quadro and Tesla cards), then doing a bottom-to-top release does not make as much sense for them. I don't believe this roadmap is true.
If Nvidia was bent on releasing smaller 28nm chips before the Kepler flagship comes out, it will be with die shrunk Fermi's for the laptop space, to fill the gap between now and Ivy Bridge.
Without going into specific financial information, generally speaking, the
discrete graphics division is also very important. Certainly, NV does not make only 10% of its profits from discrete graphics vs. professional graphics cards. While the profit margins are incredible in the professional space, the volume is much lower.
The delay most likely has to do with manufacturing/power issues, etc. I don't think NV would purposely delay Kepler knowing HD7000 series is just around the corner. NV's goal is probably to launch as soon as it's financially feasible (i.e., once yields on their chips are good enough).
Again, just like last time when Fermi was 6 months late, it barely affected NV, despite the amount of false information being spread on our forums (i.e., NV is finished, etc.). It's public information that NV revised GPU generations to 24 months from 15-18 months (as was stated by them several times). Also, I don't see what the big deal is for one firm launching faster than the other, even if it's by 3-4 months. It has happened in the past. If Kepler is faster or offers better price performance, then there are still
at least 18 months of sales before next big generation. The doom and gloom of launching by a quarter later than HD7000 series is blown way out of proportion - Fermi has shown that NV was easily able to make a competitive product lineup and maintain a 58-59% discrete GPU market share even after being 6 months late....
Not to mention, the market for $450+ GPUs is pretty small. NV can cut prices of GTX560/570/580 cards to still make them competitive with HD7850/70 series. Also, by the looks of it, the lower end HD7000 series won't be anything special either. In the short-term, NV only stands to lose the performance crown at the $300+ level. Even then, HD7000 series is launching in the historically slow for hardware sales Q1. It's not the same as when HD5800 series launches in the Fall of 2009, way before holiday season!!
If NV's Kepler generation is worse than HD7000, then NV has a problem. But ever since 8800GTX, NV has had the faster lineup every generation, forcing AMD to compete on price/performance (outside of dual GPU cards). Considering Fermi is already a scalar architecture, and its Tessellation performance is miles ahead of HD6900 series, there is a lot more risk with GCN rather than with Kepler.
Fermi architecture has excellent scaling with higher clock speeds. NV can increase Fermi's specs without any architectural improvements, and it will already be a beastly GPU. But of course, NV is going to improve the architecture even further.