If it's not considerably cheaper than building something similar or better yourself, it won't be successful. Console gamers aren't going to spend that much on a device, and PC gamers who want a "steam box" will have no problem building something themselves.
Steam Deck was released at a lower price than the same device would have cost from another brand because it subsidized part of the cost of attracting people to its ecosystem and its newly launched OS, and because that motivated people to buy more games (in fact, there was even a news story at the time saying that people who bought a Steam Deck went on to buy more games than before they had it), so I wouldn't be surprised if this case were similar.
If they manage to achieve a great price/performance ratio, even I, who have a powerful PC, would consider having this little box under my living room TV for less demanding games from my backlog.