• Even the Wii had better sales, but clearly not the same longevity 

It is early to say but with Microsoft leaving consoles behind the ps5 should do very well.

I think the PS5 will outsell the PS4 and Switch.

Its already breaking records with a $500 price tag, selling and growing in markets where Nintendo or Microsoft aren't even selling in, and SIE IP's have never been more popular. I think there is more incentive for Sony to actually cut the price of the PS5 too.

DS and PSP aren't consoles. 

Someone either hasn't heard about the Series X/S, or fails to comprehend that expanding their brand to give consumers options includes keeping their consoles as one of those options.  As long as dedicated home consoles exist, MS will have a console on the market.

In short: it's too early to tell.

My prediction though? At the rate the Switch is going, unless sales drop like a rock, it is on pace to sell 120-130M minimum. The PS5 has a great start, but 120-130M is not standard for consoles. In fact, only two consoles have ever broken that record with a third coming up. Also, the PS4 sold really well because it was the de facto console. All third party games ran better on it by default, plus it had killer exclusives. There was little reason to get an Xbox One (unless you enjoy Gears and Forza). Series X, however, has hardware that is at the minimum comparable, and on paper better (though real world results are showing a slight edge to PS5). If MS gets their head in the game and deliver on avowed, fable, everwild, Infinite, and Hellblade 2...I could see it eating into the market share. Instead of a 3:1 split in favor of Sony, I could see a 5:3 or, at max, a 4:3 split. If the first is true then PS5 will sell 110M with Xbox selling almost 70M. If the latter is true then PS5 will be at 100M and Series X will be at 75-80M.

I think the Nintendo Switch will be clearly superior to the PS5.
PS consoles have record-breaking launches but Nintendo portable console sales are much higher afterwards

I think the Nintendo Switch will end at 140-150 million units.
The PS5 will be between 100 and 130 million.

It's easy to be reactionary now but other consoles have had good launch numbers but failed to keep momentum. Right now Sony has a high demand for a limited product. Maybe they are limited or maybe Sony is pulling a Nintendo with artificial demand. Either way, let's see what happens when it's readily available in stores. When the stock is plenty and anyone can easily walk in and buy one. Sony is usually great at keeping momentum, however. It's too early to predict what will outsell what. I'm not convinced it will outsell PS4 yet. Just too early. It doesn't really matter tho. One enjoyment of a console should never be tied to how much it sold. As of this post. PS5 and XSX are in the honeymoon period and I am seeing a lot of people not realizing that and just being reactionary/ "best ever console" "Outsell PS2" yadda. It's too early to praise or damn anything really.

Too early