There was a sharp intake of breath on RTÉ's morning sports bulletin when it became apparent that Shane Horgan was about to commit an unofficial act of treason by stating Ireland might lose their opening Six Nations game against Wales. The Irish rugby team has been such a reassuringly good-news story for so long that nobody really wanted to hear such Bolshie talk. Talk about talking down the economy.

Horgan was one of the debut players chosen on that trippy week in 2000 when the national coach Warren Gatland threw caution to the wind and fielded a radical Irish selection. It marked the beginning of a prolonged period of thrilling days for the Irish rugby team and public.

He scored against Scotland and, of course, scored too some seven years later when Ireland hosted England in Croke Park, collecting a deft cross-kick from Ronan O’Gara with an overhead catch and crashing down at the Canal End corner. The try was almost like a salute to the GAA cognoscenti gathered in the stadium, stunned at the fact that they had let the oval ball into the cathedral without incurring the wrath of god.

By then, buoyed by the popularity and slick marketing of the Heineken Cup (there was always something hollow about such a big, engaging competition being named after a beer rather than a revered figure or place within the game) and by the momentum of the Irish provinces, the national rugby team found itself occupying the residence occasionally filled by the national football team. Ireland went – and has stayed – rugby mad.

Irish teams played with magnificent honesty: they turned up and with the unhappy exception of the 2007 World Cup, they managed to combine professional standards of play and coaching with the still-deafening heartbeat of the amateur imperative, when soul and a near unhinged pride in playing for Ireland were the chief resources which a lost generation of gifted Irish players had to call upon.

Horgan grew up watching Irish rugby teams act as fodder on icy Five Nations winters when the Scots had our number and something in the way the Welsh carried themselves made you suspect they just didn’t rate Ireland. Days in Twickenham were something to be frightened by. France didn’t so much play rugby against Ireland as amuse themselves. You kind of pitied the Irish players sent out there.

Horgan had witnessed all of that and yet was part of the jaw-dropping group of Irish players who seemed to cast off that cloak of oppressiveness effortlessly. It goes without saying that Irish rugby from 2000-2015 revolved around the totemic figures of Brian O’Driscoll and Paul O’Connell. And it hasn’t been acknowledged quite often enough that Ronan O’Gara was an omnipotent figure during that period too. He was, of course, an enjoyably contradictory character who managed to alchemise an emotional, opinionated personality into a wonderfully cold and precise outhalf with a killer’s instinct for goal and territorial kicking.

Big plays

People remember the drop-goal to win the Grand Slam for Ireland – the day of days: the country truly on Skid Row, Jack Kyle in the crowd, the first perfect winter since 1948; it came at the right time. But O'Gara was a habitual maker of big plays and a streak of greatness ran through his play.

There was always an unspoken realisation that it was just a brilliant stroke of luck that these three came through in the same period of time. And tomorrow, with O’Connell gone for good, marks the official ending of that era.

And now there is an unmistakable atmosphere of trepidation and glumness informing the countdown. The anxiety surrounding the concussion scare to Johnny Sexton illuminated the extreme burden now placed on his shoulders.

The guesswork as to the likely make-up of the team – and the surprises it contained – showcased how much has changed and how quickly. And there was plenty of food for thought in Matt Williams's conversation with the Second Captains crew this week about the relevance of the Six Nations to the Southern Hemisphere. He was trying to set his full recognition of what Joe Schmidt has achieved – and his personal regard for the man – against the bigger canvas of where Irish rugby is travelling. His central point, delivered with no glee, sets a bonfire to so many vanities.

“The Six Nations as a tournament has deteriorated so markedly that it is heartbreaking. There is not one word about the Six Nations in the Australia and New Zealand media down here. People don’t want to watch it. They can’t sell the TV rights down here. Nobody wants to buy it. Because it is not entertaining. It is not attacking rugby. It is not the way the game is being played.”

It is hard to argue that the brand of rugby played by Ireland over the past couple of seasons has been fun to watch. And after the most hyped World Cup build-up in the tournament’s history, Ireland failed to do any better than previous Irish teams did.

On Sunday, Wales will use Jamie Roberts to explode holes in the middle of the Irish defence, a tactic that was sufficient to unhinge Ireland as far back as the 2011 World Cup quarter-final. Watching Schmidt's defensive strategy against Warren Gatland's confrontational, powerful side will provide the immediate spectator enjoyment and intrigue.

But part of the reason that the golden decade of Irish rugby was so memorable and cherished was that it was fun to watch. The impudence and imagination with which Ireland ran the ball engaged hearts and minds, and there were days when watching Ireland play rugby was a carefree experience.

This weekend, something of the old heaviness has returned. It remains to be seen whether or not Jared Payne is the long-term answer to the gaping void left by O'Driscoll. And it remains to be seen how Ireland survive a winter without the redoubtable presence of O'Connell. But these are localised issues. The countries involved in the Six Nations resume enmities in the midst of a collective crisis of identity caused by the chastening outcome of the World Cup.

Painful results

Are Ireland playing to try to win a few more championships or are they willing to endure a few painful results in order to try to build a side capable of competing at the elite end of the World Cup? Can a country of Ireland’s size realistically hope to do that anyhow? And can the next generation really hope to live up to the dreamlike legacy of the era just passed?

When Ireland rugby was enjoying its long unbroken summer, there was general recognition of the fact that this was a really special moment. And the thing about special moments is that they come about only rarely.