Ulduar today is a raid held in high regard. It was an absolutely massive raid with 14 bosses in total, with some of them being optional, and one of them being secret. Many bosses had a hard mode that could significantly change the way you would fight a boss, and was imo, pretty revolutionary in wow standards. Not to mention the massive amount of achievements in the place, with a lot of them not even being required for the meta.
Yet despite all of this content, blizz released ToC a mere 4 months later, a raid with only 6 bosses with only two rooms and no trash. While there were guilds pushing Alg, yogg 0 etc. when ToC came out, for a majority of raiders, Ulduar became irrelevant. So why did blizz cut's Ulduar's life so short? Were they scared at how all of those naxx guilds were struggling through it? Were they not satisfied with Ulduar? I've heard some talk that Ulduar actually wasn't as liked when it first came out, did that have something to do with it?