You seem to be equating "highest quality" with "best", which is unfortunately not how the world works. To echo wfsp, the highest possible quality would mean meeting the specification perfectly. This is of course not necessarily the "best" product depending on your view however, for example:

• the spec itself may be slightly or deeply flawed, and then even a perfect quality product ends up failing in operation as a result;
• the spec may not foresee future needs, and the resulting product could be fine initially but hit some portability/scalability/expansion barrier in the future that could have been avoided by better initial design;
• to meet all users needs, strictly speaking you'd really have to interview them all, but that's not often going to happen, so inevitably some will not be happy with the result, even if it meets the spec;
• the "best" solution may include characteristics not explicitly called for in the spec, and hence will cost more, so a competitor will get the contract;

In all these cases, the product would be subject to significant criticism and likely not often considered to be high quality, yet in all cases the product could be of highest quality. Does anyone have access to Microsoft's internal specs for Excel? Maybe it's already better than it was intended to be!

I'm sure others have gone through the "Total Quality Management" era (translation = don't give the client any more effort than they paid for), and now we're in the ISO9000++ era (translation = be able to describe exactly what you did). Do these result in better products? More consistent perhaps, but not better in my opinion.