I had a thought the other day of when failed and underperforming platforms hit their point of no return. I will give some of my thoughts in this initial post so that you all can discuss what you think after seeing some examples.

Saturn: E3 1995. Saturn killed itself in the global market after rushing to market in North America and costing $100 more than PS1.

N64: Holiday 1997. The double-whammy of Final Fantasy VII and Gran Turismo in 1997 (and their sequels in the future) were simply too much for Nintendo 64 to deal with for the rest of its life. N64 may have gotten LOZ: Ocarina of Time for Holiday 1998, but it wasn't enough. N64's droughts and high software prices were simply too much to come close to the sales of PS1.

GCN: September 2003. Most of the GameCube's heavy hitters released by this point and even a new aggressive low price of $99.99 (down from $149.99 and the launch price of $199.99) was not enough. Even the new kid, Xbox, sold about 3 million more globally despite being a nonfactor in Japan. 

PS3: Launch. Yup, PS3 sealed its fate of selling under 100 million and a lot less than its predecessor right at launch. The high price and bizarre architecture for devs and the lack of enthusiasm were palpable. 

PS Vita: Launch. 3DS was already saving itself and Vita had a high price for memory cards and a lack of interesting software. 

Wii U: April 2013. Could the Wii U with some changes at this point have matched or exceeded GameCube's sales? Sure. But it didn't happen in real life. Wii U had a successful Holiday 2012 launch and then squandered the first half of 2013 with severe software droughts. The hardware units sold were dire in early 2013 and Wii U never really sold except for holiday seasons for the first few years.

Xbox One: Unveiling. My goodness was the unveiling a disaster. Microsoft had to fix itself after this big time to hit the lifetime total of about 58 million. The gen was lost before Xbox One and PS4 even launched. 

PS3 sold a crap load, it should not even be listed. It had a bad start and recovered well.

Xbox Series: When they started bringing their first party games to Playstation.

Excellent point. I was more reluctant to put it in my initial post because it's a current platform that hasn't been replaced yet. But yeah, it was already selling well below PlayStation 5 and now it is going to sell well below even Xbox One. 

Unless Microsoft wants to endlessly pour money into Xbox forever, it is truly looking like more than ever that Xbox 5 will be the final Xbox console. Even if it ends up selling over 30 million units what will even be the point anymore by the early 2030s? 

Given the sheer shift in publisher behavior towards multi-plats at the time and how the X-Box was suffering the red ring of death at the time, I'd say its warranted enough to be here.

Yeah the PS3 was definitely a console that underperformed.
It's final total wasn't terrible, but it sold about half of its predecessor and took Sony from completely dominating the competition to barely scraping out of third place.

Sales don't tell the full picture, the PS3 from a profit perspective was the worst console ever, PS3 wiped out all the profits Sony had earned from PS1 and PS2 generations put together, no console has lost any company more money than PS3 lost for Sony. Its hard to ever top a disaster like the PS3.

PS2 was the most succesful console ever. And all that money it generated was just swept away by the PS3, it would have been like the Wii U wiping away all the money Nintendo earned during the Wii/DS generation.

Since the market has been growing every system that was less profitable than its predecessor in the same timeframe is to an extend failure.

The biggest fails where PS Vita, Wii U, GameCube, Xbox One and N64. Not saying those are failures since especially the OG Xbox and N64 had very impactful games, also Wii U provided Switch with a lot of ports that sold millions. But from a business point of view it was not what they had envisioned.

Even though the gap between PS4 and PS5 is likely to grow, it's still a success since it's much more profitable.

The moment the rumors began heavily spreading over the wide net until Xbox did the famous Xbox updates video (which aged like milk already), it was over.

Though, arguably the underperformance of Stanfield and the rest of their big hitters last year were telltale signs of that.

Dreamcast - Reveal of the PS2.