For the Dreamcast, specifically, there was a show on G4 (on cable, before merging w/ TechTV) that I remember casually watching a bajillion years ago that discussed what happened with the Dreamcast. Basically, the PS2 is what happened.

There's this 5 second blip of the program that burned itself into my brain where someone from Sega was talking about how awesome and exciting things were one moment, and then PS2, then *cricket sounds*. They mention how they had to stop production because they literally had warehouses filled with Dreamcasts just sitting there.

It was kinda nuts for them 'cause the Dreamcast actually sold pretty ok until people learned about the PS2's price and the fact you could watch DVDs on it, which alone was huge. Sony just fuckin instantly annihilated everyone so hard with the PS2. It wasn't feasible, timewise or financially, for Sega to iterate on a new system fast enough and somehow dump all the systems they had lying around, and they knew if they wanted to contiue to exist, they had to switch gears to be mostly software/publishing, aside from arcade cabinets.

Though (to me, sadly) Sega shed the last of their arcade board-makin days in 2021, they are the reigning champ and legends of bigass video game machines. They made more than 500 arcade games and produced over 20 arcade system boards that ended up being able to run stuff like huge Unreal Engine 4 games on dual 50" screens. They sold the last of their arcades back in 2022, leaving a pretty dope legacy behind, even though they're still kicking around otherwise. I guess COVID was to their arcades as the PS2 was to the Dreamcast.