I didn’t ask which system generated the most revenue nor which was the most profitable, but commercially successful. So software-to-hardware ratio, for instance. (Also PS4’s software figures are inflated by digital only software. Nintendo excludes those in their fiscal reportings.)

Actually, PS4 official software numbers do not include digital only software, nor do they include pack-in titles(Nintendo software includes pack-ins). Sony only started including both during the March 31st 2021 accounts. Interestingly they give the year before results(using the new system) so for FY ending March 2020 we know what the PS4 software was under both systems which is useful for understanding the difference between the methods. For that year it was 245m and using the new system it was 276.1m. So pack-in titles + digital only game sales for the year were 31.1m. With Nintendo already including pack-in titles and having a lower digital percentage, and lower software sales overall, it’s likely if they included digital only games it might only be an additional ~10m a year. 

PS2 for me.

It is hands down the most successful console of all time. But it isn't necessarily the most popular. Popularity is determined by engagement, spending, and software sales in addition to hardware sales and other factors. Success is primarily gauged by profitability.

The PS5 may end up coming close in profitability despite everything it's gone through.

As far as "significance" though, the most successful consoles of all tlme are NES and PS1.

I mean, it's no Ouya.

Well clearly the answer is PS4.  If Nintendo doesn't share then its unknowable which would make this topic pointless.  PlayStation numbers are not inflated... they just are what they are. But if we base it on actual knowable stats then we could have a conversation.  Otherwise it feels like you have a topic no one can verify or dispute.  It come across as a litmus test to see if everyone else loves Nintendo as much as OP.

Well I do quite love me some Nintendo! (You have eyes: Do you not see that my profile picture is literally a picture of Mario? And that like 90% of my posts are Nintendo related?)

Anyhow, you can read my OP for some statistics that I had in mind. No price cuts, strong reliance on first-party, not coming off a strong predecessor, etc.

Im a huge Zelda fan as im sure my profile pic highlights.  I made a game but the visual esthetic is based on Zelda.   Im also a huge fan of Mario. 

But yeah im saying that a claim of best commercial success can be derived through metrics that can be measured.  Im a data guy.  Like hard numbers and I dont think we have the data to really make that claim.  Thats not your intention here and I apologize for any misunderstanding.  

As people have said, there are different metrics for most successful: The most systems sold, most profitable, most dominant for its generation, etc.

Personally, I'd probably give it to the NES, as it was the system that established home console gaming as a permanent form of entertainment. It was a global success (moderately in Europe, massively in NA and Japan), set parameters that became standards going forward, single-handedly revitalized the crashed home console market in North America and popularized a slew of IPs that became synonymous with gaming. No other system can claim all of that.

Another area where it'd be up there would be the number of megaton sellers; it has 21 games over 10 million, (with more like Mario Party Jamboree and perhaps Tomodachi Life set to add to that number) 9 games over 20 million, (again, a number that could grow by the time all is said and done) and 5 over 30 million. (Potentially 7 by the time sals stop)