I don't see what they could get out of the market.
Nintendo are very successful, yes, but you can't separate the draw of the Switch being handheld-capable from the draw of evergreen exclusive Nintendo first-party IP. Nobody else has come close to making a successful mass-market handheld in the smartphone era. Without either a novel new USP piece of tech that no other console or phone is doing, or Nintendo-level exclusive coverage, I don't think there's much of an audience for a new handheld no matter who's releasing it.
Nintendo are very successful, yes, but you can't separate the draw of the Switch being handheld-capable from the draw of evergreen exclusive Nintendo first-party IP. Nobody else has come close to making a successful mass-market handheld in the smartphone era. Without either a novel new USP piece of tech that no other console or phone is doing, or Nintendo-level exclusive coverage, I don't think there's much of an audience for a new handheld no matter who's releasing it.