Has anyone else ever reached an audio impasse?

Perhaps I should explain -

A friend of mine has a VERY high resolution system which would retail close to the $100K mark. Each component upgrade he has made over the years has been based upon comparison between components. He has built a fantastic system.

Now here is the problem -
Recently he and I compared his source CD player which is the top model currently available under 15K, against a Sony 9000 ES SACD/DVD player. We A/B compared them.

After extended listening, we found the differences to be so minor that it was difficult to detect which was better. We did the comparisons with Redbook CD vs SACD, RedBook vs. Redbook and still the 15K CD player was only marginally (.05%) better.

The 15K CD player had better more expensive interconnects and power cords than the Sony which was using a stock power cord an old Audioquest Topaz (cheap) interconnects.

In previous listening sessions over the past year we had compared the same Sony 9000 CD/DVD/SACD player against MANY other CD players ranging in price from 2000 all the way up to 7000 and on redbook CD's the Sony always got it's butt kicked! It sounded hollow - with a recessed midrange - electronic - over emphasized highs, etc.

Then - I took a 100 Toshiba DVD player to his house and tried it against his 15K CD player. It sounded the same as the Sony. In fact, the 100 Toshiba sounded as good if not better in some ways than the Sony DVD player but...still was .05% out classed by the 15K CD player.

With each source component in these auditions, the soundstage remained VERY large, images were perfect and tonal balance couldn't be better. The subtlety of the changes between the various source components would be best described as perceived rather than actual.

I am curious to know if anyone else has experienced this type of an impasse. I know the $100 DVD player should not sound like the 15K CD player (at least it never did before)
but it does now. Why??

Could there be a bottle-neck somewhere? Could the character of an pre or amplifier be so strong it restricts performance of a source component? What could cause this to happen?

Help please...