The Scarlets outgunned their Welsh rivals by four tries to two on Friday night and the Blues ended in seventh place on the Magners League try-scoring lists with 37 from 22 outings compared to 31 in 18 the previous year.
"I'm hugely frustrated and disappointed that we didn't get into the top four, but in rugby you get what you deserve and we didn't deserve to win," admitted Young.
"We knew what we had to do, but we simply couldn't do it. We stuck in for as long as we could, but the better team won."
The Blues had to go to Parc y Scarlets and win to become the sole Welsh representative in the top four, but they fell short once again as the Scarlets gave Regan King a royal send-off after six years in Llanelli with a 38-23 triumph.
For a short while, with the Ospreys losing against Aironi in Italy, it looked as though it might be the Scarlets who would be extending their season. But then the Ospreys found a get out of jail card and scraped through 12-10 to overtake both their Welsh rivals.
After two successive seasons of winning trophies (the EDF Energy Cup in 2009 and the Amlin Challenge Cup in 2010) and reaching the knock-out stages of the Heineken Cup, Young has seen his Blues side slip to non-qualification in Europe and sixth in the Magners League.
"I am not going to criticise my staff or players in the media. When we win it is always a collective effort and when we lose it is my fault and the buck stops with me," added Young.
"We have always moved forward in the eight-nine years I've been with the club, but this season I think we have gone backwards for the first time.
"Our big problem is something that has followed us all season, which is our ability with the ball. We have scored 37 tries all season, which isn't enough.
"You aren't going to win games if you don't score tries. Our attack has pretty much let us down and has been our Achilles heel."
Chris Czekaj scored on Friday but the Blues haven't done enough in attack
Young has been severely hampered by injuries this season and has lost the services of the hugely talented and dependable Tom Shanklin to a knee injury after a wonderful career. New Zealand international full back Ben Blair hasn't played since September and the Blues had to do without Welsh caps Jamie Roberts, Tom James and Richie Rees for long periods of the campaign.
So how can Young make improvements next season? Simply by getting more out of the same group of players.
"It's not a question of can we do better with this squad of players, it is a simple question that we have to do better. It is well documented that we won't be bringing anyone else in next season," he said.
"We've got this squad and it is up to us to get more out of them next year. We have all got to look at ourselves and look at how we can improve.
"It's a simple equation - we have to get more out of ourselves next season because there is nobody coming in to help us get better."
Having come up one point short of the Play-Offs last season, and three this term, Young will now have to watch the Ospreys represent the Welsh regions in the business end of the Magners League campaign for the second year in a row.
"The Ospreys have got the ammunition to kick on and win as they showed last year. They are proud champions and they will want to defend their title.
"It doesn't matter how you get into the top four, once you are there you can kick on. As far as I am concerned we are fully behind them. The league doesn't lie and they deserve to be there."
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