I'm sure 25+ Million sellers like GTA, RDR, 20+ Million sellers like COD, 10 - 15 Million sellers like Fifa & Star Wars don't eat into SIE software sales. /s
Hold on, you think MK8 is "well on route" to hit 40 - 50 Million on just the Switch, when it might not reach 30+ Million until 2022? Yeah, Mario Kart is not moving those kind of units, otherwise it would be well past 30 Million lifetime at this point in time. 50 Million is a pipedream unless Nintendo ports Mario Kart 8 for their next console. Again, I'm not sure why you think SM is capped at 20 Million lifetime, it can easily finish with 25 - 30+ Million. Its not like PS4 software is going to stop selling in 2021. Take TLOU, which sold 10+ Million units on the PS3, likely half of those sales coming after the PS4 launch.
Why are you attributing Switch hardware sales to just Nintendo software sales? Switch being a hybrid console is a big factor. Look at the WiiU or even the Gamecube. It had many, major Nintendo IP, and still ended up as an absolute embarrassment. Even the novelty of the Wii was a bigger factor in moving units compared to Nintendo exclusives. Of course, Sony won't hit 120+ hardware sold without third party support, but Nintendo exclusives don't guarantee 100+ Million hardware sold either, they might not even guarantee 30+ Million units. I don't use handhelds in this comparison because its a completely different market (lower price of entry, lower priced games, different tech expectations, etc). What do you think happens if PS4 hardware and software prices follow the DS hardware and software prices? How about the other way around?
You're downplaying the legs of PS4 games while giving the best case scenario for Switch titles. Mario, BoTW, BoTW2, Smash, Pokemon, are now all on pace for 30+ Million lifetime? Please. Nintendo IP making 30+ Million units sold look like child plays is just another pipedream. Most of those games will finish around 25 Million lifetime, BoTW and Mario aren't even at the 20+ Million mark yet. If you think the Switch will finish with two titles that sell 50+ Million units, its no wonder why you think Sony isn't close to Nintendo's level, since you're living in some kind of dreamland. How about you have a realistic assessment about Nintendo software sales before posting.
Mario kart was at 29 million at the end of September. It already definitely passed 30 million by now. It seems likely it will end somewhere between 40 and 50 million by the end of the switchs life.
I cant see spiderman selling millions more on ps4 when it's already got a remaster on a new console. Also any source for that last of us ps3 number, because this is the first I've heard of it selling over 10 million on ps3.
I agree that it's doubtful that those games will reach 30 million. Although I'm not sure why you think they can't and spiderman can?
I'm not sure if you can call anyone unrealistic when you think that spiderman will sell another 10 million on a replaced console and has already been remastered on the new console. Spiderman ps4 is done I doubt it'll sell another 1 million on the console. I don't think AC or MK will manage 50 million on switch but there's more of a chance of that happening then spiderman hitting 30 million on ps4.
In my opinion Sony hasn't quite hit Nintendo levels of sales with software yet. But they might be able to do it this gen. They've improved software sales massively over the last decade, so it's definitely possible to hit that level at some point and maybe even surpass it. Once they have a game that can hit MK levels of sales, they will be on a similar level.