Almost all popular Google products (other than search and Gmail) have come from acquisition: Maps, Analytics, Google Apps, Android, Blogger, Picasa, YouTube, Postini, reCAPTCHA, etc.
My good friends Robby & Wayne's company, Zenter, was acquired by Google in 2007. While Robby has since left, Wayne is now a very respected eng manager in charge of a very important project, so I would argue that acquisition was successful for them.
So while many acquisitions do not work out well (and usually loudly), it would be a big mistake to pretend that applies to all acquisitions.
You're right; some acquisitions survive as real products and it would be a mistake to call them "failures".
I guess what the OP means is that price alone is not a sufficient criteria to judge whether an acquisition was a success. If you sell your company for a large amount of money, but it gets shut down, that's not "success" (although it's certainly much better for you than closing down without any money).
Same with Adobe. Everything in their creative suite except Illustrator was the result of an acquisition. They had a lot of botched and failed acquisitions over the years but there's no question they wouldn't be where they were today if not for a series of very smart acquisitions.
My good friends Robby & Wayne's company, Zenter, was acquired by Google in 2007. While Robby has since left, Wayne is now a very respected eng manager in charge of a very important project, so I would argue that acquisition was successful for them.
So while many acquisitions do not work out well (and usually loudly), it would be a big mistake to pretend that applies to all acquisitions.