This is completely false. My guild is just starting out here, and we're more than excited to start doing Naxxramas, despite current content being Ulduar, and it would of been the same regardless if it was ICC or not. The last time we rolled on a Wotlk server we were bummed that we couldn't even do Naxx or Uld, because the gear catch up dungeons completely removed the need to even do those raids. No one wanted to do them, so we couldn't even get a guild that wanted to farm them, or progress normally without touching catch up dungeons.
On top of that, look at the demand for Vanilla and TBC content. TBC offered isle of Quel Danas and badges, but even then, you didn't by pass Kara, and go straight into SWP. You still raided from the start, all the way to the end. Players STILL started at Kara, and moved up through content, while Black Temple and Mount Hyjal was on farm, and players were content with it, because it was still new to them, they were just starting out.
Catch ups DO NOT remove incentive for new players to start here. If anything, they hurt the population, and quality of players. Gear catch ups handed anyone an epic, and allowed them to skip raid content. They opened up raiding to players that had absolutely no raid awareness, it was like a flood gate of idiocy opened when stuff like this started popping up, especially coupled with Gearscore. You couldn't distinguish who was a seasoned raider anymore, or who just sat in those dungeons for loot, because someone out of Ulduar, or someone in catch up loot, were on par gear wise. Which is where a lot of people felt GS ruined the game, because you would literally either be inviting a complete ***** to the group, or a good player. You never knew. You almost literally never knew what you were getting. Before these catch up dungeons, when I saw someone walking around Dalaran decked in Ulduar raid gear, I at least knew the player was good, because not every guild is willing to drag dead weight through content and drop gear on them. It happened, but it didn't happen a lot.
On top of that, since you skipped TWO whole raid tiers and jumped into these dungeons, you effectively cut out half the end game PvE content, and half of what was there to do. So yeah, you can skip everything and go to ICC.. And youre done. I don't know about you, but if I just cleared current content, im' not about to start over on another toon and do it again. I'd literally get bored and quit. Starting at Naxx and working up to ICC would prolong a players stay here. Why would they quit after Naxx, if they had 3 more raid tiers of content after it?
Plenty of people will start at the bottom in a year, and ENJOY IT. This game isn't about how many corners you can cut, its about the journey, and for many, the journey starts at end game content. What kind of journey are you going on, when you literally bypass all of it, to do the final raid? You miss out on a lot. You should never be able to start a new account, and go straight to the "final boss" in a game like this, in a matter of weeks. If you think thats GOOD game play, than you're the reason we have Warlords of Draenor.
There is a reason a lot of players felt late Wrath was where World of Warcraft started to decline. That however, is a different discussion, and i'll just leave it at that.