Yes, the Sega Dreamcast was released 20 years ago in Norteamerica, as a succesor of the Sega Saturn, that were come with the 3D jump of the Sonic franchise games starting with Sonic Adventure and Sonic Adventure 2, also with other memorables games like Shemmue I and II, Crazy Taxi, Space Channel 5.
Plus, in other news, you can pre-order now a copy of Mario & Sonic at the Tokyo Olympic Games 2020 for Nintendo Switch from the official site. The game will be released at November 5th, 2019.
Mario and Sonic Tokyo 2020 – Official Site.
The 20th Anniversary of the Dreamcast in the US? I wonder how long it exists in Japan.
Wikipedia says that the SEGA Dreamcast was released in Japan in November 1998 and in USA in September 1999. So yeah, the answer to your question – it will be 21 years in the next November. (⌐■_■)