Financially NeXT was a wash, the $400 million paid for it was enough to pay back most of the investors, so they got their money back but no profit.
For Apple, having the NeXT talent and what became OSX, it was a success for them. So NeXT had value - it was not a "-1" as a company going bankrupt would be.
Yeah; if a web startup sold to Google at essentially no profit when you paid out the investors, I don't think it would be considered a failure. Maybe not a great success, but certainly no one would consider it a bad thing.
And if a web startup sold to Google at essentially no profit when you paid out the investors, and the technologies pioneered at it went on to power almost every major product Google released for the following 15 years, people would consider it a deeply influential and successful company.
People seem to grade NeXT on a very, very steep curve.
NeXT is a confusing company to judge. They were slowly dying for years, then suddenly Apple came along and rescued them. Except it turned out that it was NeXT who rescued Apple. But all the subsequent stuff was done under the Apple name, so people just remember the NeXT that built extremely expensive computers, didn't sell very many of them, and nearly went bust before being bought out.
For Apple, having the NeXT talent and what became OSX, it was a success for them. So NeXT had value - it was not a "-1" as a company going bankrupt would be.