Not really. The N64 had extremely popular first party games. That's what saved Nintendo's console from going extinct. Another factor in Nintendo's survival was the global popularity of their handheld consoles. Even if you were not a N64 owner, chances are, if you owned a portable console, you had a gameboy.
The Dreamcast didn't have that privilege. I'm not saying Sega's first party games were bad, but they were nowhere near the kind of popularity (I don't necessarily link popularity to quality) that could sustain a console maker. As for Sega's attempt to enter the handheld market, it began and ended with the same console, the Gamegear. It's still a mystery to me why Sega dropped that market, it didn't sell as well as the gameboy but its sales were still very high and well within the scope of what would qualify as a success, it was a much better console than the various Gameboys until Nintendo released the GBA too.