There are layers to Scotland's failure.

Some blame the manager's inability to get the best out of his group of players and want him removed despite his new four-year deal. Some cut the manager some slack by saying the players, though hard-working and fiercely determined, are over-praised and over-rated at this level.

Others look deeper at the woeful inability of the Scottish game to develop athletic young talent and the aversion that top-flight clubs have in giving youngsters a chance of first team football and say what hope have you got.

The truth is that it's a mix of all of these things - plus other things.

Scotland were in an extremely tough group with the world's fifth and sixth-best teams. One win and two defeats is what most people should have expected, albeit the win was hairy and unimpressive.

There was nothing surprising about what Scotland did, or did not do, against Morocco and Brazil. Those teams are better, pure and simple.

Clarke is being pilloried for being overly negative in the way he set his team up, when he really wasn't. He's getting hammered for not getting the best out of what he had. That's a moot point.

He's been in charge for seven years and has taken Scotland to three major championships. That's a fine legacy, and it has now reached its end point despite just signing a new deal.

There is a notion that Scotland's team is packed with quality, but that argument doesn't hold a lot of water, if you're being brutally honest.

This is a squad full of endeavour. There are good to very good players sprinkled around the team, but the collective is decidedly average, at best, in the rarefied air of a World Cup.

This is not to denigrate players who have bust a gut for their country; it's an attempt to explain the real world they live in. Angus Gunn can't get a game for Nottingham Forest. Aaron Hickey is an excellent player, but he's jinxed by injury. Nathan Patterson struggles to get game time with Everton. Jack Hendry just finished seventh in the Saudi Pro League. Grant Hanley, for all his fantastic resilience, is not a high-end international defender.

After an error against Morocco, Hanley was replaced by Scott McKenna against Brazil. McKenna made a catastrophic error after seven minutes. He's a good player who has just won the Croat league with Dinamo Zagreb.

The number of Croatia-based players in their World Cup squad: two. The number who have featured in games so far: one.

In last season's Europa League, Dinamo finished 23rd in the group of 36, so at a higher level, McKenna's team struggles because his team, frankly, is not top European class.

Kieran Tierney is a terrific footballer but injuries curtail his influence. He's played one 90-minute game all season. Andy Robertson has been magnificent for many years at Liverpool but last season the majority of his Premier League appearances were off the bench.

Scott McTominay has been much talked about. The talisman who was not very talismanic when going up against the really big boys in midfield.

McTominay is capable of wondrous individual moments and is, unquestionably, one of the real stars of Serie A. The issue here is how good is Serie A?

Napoli were champions of Italy two seasons ago but in the Champions League last campaign they won two games from eight and finished 30th in the table. Serie A, and Italian football in general, is not what it used to be.

The Azzurri have failed to qualify for the past three World Cups. Expecting McTominay to light things up in America just because he lights things up for Napoli was too big a task for him.

John McGinn is beloved. He's done so much in the Scotland jersey, but the "Super John McGinn" song has now become more of a plaintive cry than a statement of fact. McGinn needs strong players around him in order to excel, as he does as Aston Villa's hugely respected leader.

Clarke played him on the left - not his best position - because he needed Ben Gannon-Doak's pace on the right. Gannon-Doak is a really exciting prospect but his elevated status with Scotland belies the fact that he's been injured and has only played 150 minutes for Bournemouth this season.

Ryan Christie, another admirable player picked out of his best club position, has started only nine league games for Bournemouth with another 17 appearances as substitute.

The impressive Lewis Ferguson was probably the pick of Scotland's players in America despite not always being a guaranteed starter for Bologna.

None of Scotland's strikers landed a blow, in part because they had precious little to feed on. The ones that played put in hard but fruitless shifts. Not one of these guys lacked for effort. They were clearly desperate to do well.

The bigger picture is what happens next.

Has anybody any clue about how to make things better in the years ahead? The manager spoke about the need to produce more athletic and dynamic players going forward, but how is that possible when Scotland's clubs are so reluctant to give young players a chance?

This is not a cry for today, it's a cry that's been heard for years and nothing changes. Scotland has one of the oldest squads at the World Cup and a number of them will probably retire now. Down the track, there's a player crisis lying in wait.

For now, it's the slowest of retreats from the States, the memory of those early days in New York and New Jersey now dimmed, the hope of the 4-0 win over Bolivia crushed to bits.

Weeks ago, Clarke said he was a changed man, but the endgame is just the same. They did well to get here, but once again it's the staying here that's beyond them.

Blame who you like - manager, players or no-one at all - but the sad reality is that a side that scores one goal via a double deflection against the 83rd best team on the planet has no business being in the last 32 of the World Cup for all of their effort and honesty.

The supporters? Now that's a glorious tale that will be told for the rest of time, long after the football is forgotten.