That is true, but I think moreso untrue. It is true in the sense that yes, sequels in popular brands often sell more than new IP, because people are familiar with the brand and feel confident that they will enjoy the new entry. Less risk of not getting their money's worth.
It is untrue in the sense that every popular brand was once a new IP. Halo, Mario, Sonic, Assassins' Creed, Battlefield, Uncharted, etc. were all in the same position as games like W101 and Puppeteer. Maybe some had better marketing than others. Some, like Mario, Halo, and Sonic had the opportunity/challenge of defining an entire platform holder. But all were new IP, all of them had to overcome challenges from opponents who were already established in the industry, and none of them were guaranteed major success.
This year has seen, and will see, new IP, and some will do better than others. W101 and Puppeteer may not do to well, but Watch Dogs looks to be a big success. Ryse, Knack, and DriveClub will all have their opportunity to shine. And next year we will continue to see a variety of new IP; Destiny, The Division, The Crew, Child of Light, Project Spark, D4, Below, Transistor, The Witness, and others will have the chance to hit it big, and some will, and some won't.
So ultimately, I don't think it is fair to blame the failure of a new IP on the popularity established brands. Every year new franchises are created, especially now that we are fully entering a new generation, and plenty of those new IP will be quite successful, and maybe go on to build the brands that are now being criticized for taking away sales from other new IP.