I can see why this would be true to some extent. I think most people are disagreeing because people that actually use this site are comprised of gamers/tech craving people who use discrete GPU's. I mean that's what this site provides: reviews/benchmarks/articles about new tech/hardware that are coming out, and who actually views articles like that? gamers/tech people who want the best performing hardware out there, and as such they will be using discrete GPU's.
This article is true to some extent because of the significant improvement in Intel's IGP. While some might say that AMD has a better IGP and they are the ones who "killed" discrete GPU's, the percentage of people using Intel over AMD is significantly higher. So while AMD does have a better IGP, majority of the market is using Intel and the better IGP on AMD does not affect the discrete GPU as much as when Intel's IGP improves drastically like it did with Ivy Bridge. With significant improvements with IGP from both Intel and AMD, everyone now has access to improved IGP's whether they use Intel or AMD.
While most people are still using old generations of Intel and AMD, those users are most likely included in the "95%" estimate of people who will only need the IGP for everyday usage. The average user who only uses computers for web browsing/streaming/movies/etc, will not have the need for the latest and most powerful technology as their current system serves them well enough for what they use their computers for. When people eventually feel the need to upgrade, whether it's for performance reasons or marketing temptations, their choice of upgrade will be either Intel or AMD which both has significantly more powerful IGP's. This will eliminate the need for lower end discrete GPU's as the average user can get by with the IGP in Intel or AMD.
This only leaves the remaining "5%" of hardcore gamers who will be using discrete GPU's. When looking from a big picture perspective, if 95% of the market no longer has a need for discrete GPU's, does that not in fact warrant the phrase "killed discrete GPU's"? The remaining 5% is a very small percentage of the market and while they will still be using discrete GPU's, the majority of the market will no longer have a need for it. With the improvements for IGP, the discrete GPU market becomes a niche/focus for the remaining 5% hardcore gamers.