This was all because of Sega's incredibly stupid marketing of the Saturn, the PlayStation was so beloved that the hype for PS2 was going to kill the Dreamcast no matter what. Dreamcast is definitely a cooler piece of hardware in some ways and its sad that it died an early death but the PS2 was probably the perfect console for the perfect time. Its the greatest console of all time imo. The library is staggering and very quickly after launch many amazing games were releasing at what felt like a weekly pace for like 5 years straight. Its a totally different era I wish we could go back to.
Imo the Dreamcast wasn't even the weakest console of the gen, it was the GameCube. GC had a handful of great exclusives but everything else about it was a total afterthought and there was a pretty shocking amount of multi-plat games that even skipped the GC. Also I'm in the camp that does not really care for the GC controller aside from some games like Sunshine or Melee working well with it. Otherwise it feels tiny and uncomfortable.
PS2 >>> Xbox > Dreamcast > GC but they were all good in their own ways. PS2 just eclipsed the rest by how insanely successful it was in nearly every way, its definitive proof nobody gives a crap about hardware specs when you have the best software output in the business.