I feel like you think that I'm saying something that I'm not. I'm not saying the Switch will be a success. It is FAR too early to say that. I am saying that it is posed to have a strong launch. Also comparing X and Y to Sun and Moon is not an apt comparison considering Sun and Moon sold 80% faster than X and Y at launch. Also after Pokemon Go 3DS sales increased by 80% over previous months. So Pokemon alone created a surge in sales of the 3DS. A handheld that is basically dead. I don't think it will have much trouble assisting Switch sales when people know that they are investing in a console that will last them years.
Also the Wii U was plagued with severe marketing issues that they never managed to recover from. The Switch's marketing strategy so far seems to be going well. BTW all the sources I've seen say nothing about Stars coming to the Nintendo 3DS.