Yeah the PS3 already made its 'comeback' during its generation. And those billions Sony initially lost on PS3 made a quick end to the HD-DVD Blu-Ray war which could have costed Sony a lot more. Imagine that dragging on for many years or even HD-DVD with it's slower speeds and smaller discs having won. 4K HD-DVD wouldn't have worked, longer install times, less on disc, more layers more expensive to press and no h.265 codec.

PS3 went from a slow start to almost winning its generation (or still did in the end after the 'race' was over, 87.4 ps3 vs 85.7 360 according to Google)
WiiU went from a strong start to fizzling out rather quickly. (13.6 million according to Google)

Switch did benefit a lot from reselling WiiU games! Not only a better system, also one with a lot of software right from the start.

Switch, it's not even a question. PS3 can only seen be as a letdown after 150m+ PS2, but otherwise PS3 still had a good run. WiiU on the other hand has been a massive flop

Switch. PS4 didnt make a "comeback" of any sorts, the PS3 sold a lot, whereas the WiiU... well, you know.

WTF! PS3 to PS4 isn't a "comeback". i mean, sure PS3 made Sony bleed tons of money, but the system had 7 years life cycle and nearly 90M units sold, also won the war of formats with Blu-ray discs!

WiiU to Switch is a different story. WiiU is a gigantic Flop that failed to sell 15M units, i mean, It sold less than Playstation Vita! The only thing positive about WiiU are ALL the games ported to Switch, like Zelda:BoTW.

Like almost everyone pointed out, it's obvious the situation the Switch and PS4 started in are diametrically opposite since the PS4 was coating the tail end successfully of a generation they initially stumbled in but by the end could be considered successful, Nintendo was coming off it's weakest set in it's history and basically did the 180 not many people expected when the Switch released.

Switch of course

PS4 was not a comeback, was just Sony having a successful console as they always do

PS3 had a comeback in itself. Started as a flop and ended the generation as the most popular. So Sony was already on high grounds launching the PS4. Nintendo was at it's lowest (and one of the lowest of the whole industry) went on to have one of if not their best era. Switch is probably one of the most lucrative systems ever at this point.

I don't get consider PS4 comeback, because ps3 was successful. yea it made some big mistakes but still was successful console.

For all intents and purposes Nintendo has exited the home console market and focused purely on portable handhelds.

So they never really made a "come back" in the home console space.
Portable however...

The Nintendo 3DS > Nintendo Switch is a jump from 75~ million to 132~ million and still increasing.
That is a jump of 57~ million hardware units and set to grow which is absolutely impressive.

The Playstation 3 > Playstation 4 was less of a jump going from 87~ million to 117~ million.
That is jump of a much less but still respectful 30~ million units with Sony purely focused on the Playstation 5 going forwards so it's unlikely to change.

So without question, Nintendo made the larger comeback based on hardware units alone.

Wii U sales were a disaster.
PS3 sales you could say were mediocre.
Disaster to Gargantuan success.
Mediocre to Massive success.

Switch is obviously a bigger turnaround given the absolute Disaster that is Wii U.