It's very possible most or all 3DS models will be discontinued this year. My current bet would be Q1 2020, so right around the end of the fiscal year or sooner. I think Nintendo wants to make new models for one last holiday season. Mario Kart 7 alone has sold at least 10k+ worldwide each holiday season the past few years.
The last DS models were discontinued in 2013. Granted the DS sold about double the 3DS, but the 3DS is backwards compatible with the DS. So the 3DS still has a bit of purpose, since it's a pure handheld with no way to play its games on the Switch.
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 57 million (was 60 million, then 67 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
