I know that I do a lot of sales topics but I am very interested in the console market. We know that the Nintendo Switch has a 2.5M lead over the PS4 with one Christmas less for the Switch and it is a hit in all countries of the world. Will it exceed the PS4 in terms of sales?

For me it's a yes

Nop. Ps4 is set to reach something like 120~130 m and switch isn't making these numbers. Switch will be under 110m, perhaps even under 100m. On the next 2-3 years sales will be slow and ninty will just go for a nextgen console whit better tech.

It all depends on Sony strategy for ps4 post ps5 launch. If they do like what they did with ps2, by heavily discounting it and focusing on emergent markets in wich most of the population don't have enough purchasing power to get a PS5 and keeping games prices in check to match this reality, since most of them will be catalogue anyway, they can easily sell 140 m ps4s and switch will not reach this number because Nintendo really doesn't invest in emerging markets and probably will make a Switch sucessor in the next 3 years or so.

If Sony do with ps4 like they did with ps3, just discontinuing it as fast as possible to focus on ps5, it can sell 10~12 million units still, and maybe the switch will catch up

I bet no, Nintendo always aborts their consoles abruptly like an unwanted fetus so that they can position their next console between the Sony and Micro new hardware releases, focusing all their software for the new console.

One thing that could prove me wrong though, third party small titles that may be popular in the Switch may carry the console further than how Nintendo consoles have done in the past, but I have no idea about numbers of how well small third party titles do on the Switch so I really don't know.

If the Switch's success depends entirely on first party sales on the Switch then in will come the drought of titles as Nintendo moves to their "Catch Up Gen" release with whatever comes after Switch and with that drought so to will come the death of the Switch, put to pasture as soon as Nintendo decides to abruptly abort once again another console in favor of strategic release dates,

Yes la Nintendo Switch vend beaucoup + que la PS4 à la même période et qu'elle produit des chiffres que Sony n'a jamais réalisés avec sa PS4, tout dépendra du soutien de Nintendo et c'est bien puisqu'ils ont annoncé que le cycle de vie de la Switch être le plus long

No. Sony is better at keeping momentum in the later years of a systems life. Nintendo is kinda bad at that in general.

It's possible the Switch sells more, but feel it's more likely that it won't. Also, why is everyone I see from France named Yanis lately? I have 2 people named Yanis recently added on my PSN friends list, then you arrive at VGC, and now Ubisoft director Yannis Mallet has resigned today, apparently because he's a sex monster. So many Yans.

Switch will get around 95-100 million on the more pessimistic side, but more likely 110 million. It's not touching PS4 in the end. PS4 will sell about 130 million.

Your scenario is historically true for Consoles, but not so much for how Nintendo has treated their handhelds. Switch being a hybrid of the two, and the videogame market being very different from what it once was, there's no guarantee that Nintendo will abruptly drop support for Switch like they did for most of their home consoles. I also don't foresee there being much pressure on Nintendo to "catch up" to Microsoft and Sony from a hardware perspective as their system caters to a different market with different expectations. It's not like they felt pressured to make the 3DS catch up to the PS4 when it launched.

So gonna throw my hat in and say Switch will equal, but not exceed PS4 sales, with the PS4 having only a slightly longer lifespan.