CHICAGO — Here's the $24 million question:

Did Alex Smith fail the 49ers or did the 49ers fail Alex Smith?

The quarterback arrived as the No. 1 pick with an enticing blend of arm strength, mobility, intelligence and attitude.

Four seasons later, it all has gone terribly awry.

Smith enters Thursday night's exhibition against the Chicago Bears with only a scant chance of retaining a starting job. He probably will lose out to a career third-stringer making the NFL minimum salary.

If Coach Mike Nolan does anoint J.T. O'Sullivan his man for 2008, it also would be a tacit admission that Smith has fallen short of the expectations that greeted the quarterback on April 23, 2005.

The 49ers hoped he would look like previous No. 1 quarterbacks such as John Elway, Troy Aikman and Peyton Manning.

Instead, Smith looks like a bust.

But did the 49ers bust him?

Smith supporters argue that the promising kid got a raw deal from a team that was supposed to nourish and develop his raw talent. Smith skeptics say it's time to stop making excuses for a player who clearly doesn't have what it takes to be an NFL quarterback.

It's about the only debate left in the 49ers quarterback competition.

Revolving coordinators

Blame the 49ers: Smith has had four offensive coordinators in four years, a dizzying blow for someone with a reputation for needing time to adapt. Urban Meyer — Smith's college coach at Utah — warned as early as draft day that the brainy quarterback would be "non-functional" until he could intellectualize the system.

The revolving door of coordinators has ensured that Smith remains non-functional.

Blame Smith: There was nothing the 49ers could do to stop Mike McCarthy and Norv Turner from leaving for head-coaching jobs elsewhere. They made a mistake with Jim Hostler last year but rebounded with a Super Bowl-proven guru in Mike Martz. Handling change is part of life in the NFL, and most quarterbacks would be lucky to have the cast Smith has learned under.

Injury controversy

Blame the 49ers: Nolan undermined Smith with public swipes at the quarterback last year when Smith suffered a separated shoulder. Nolan insisted that the quarterback was fine, even when Smith was so obviously ailing that even opposing players such as Seattle linebacker Julian Peterson took note. Frustrated, Smith confessed that the shoulder was "killing" him — resulting in an ugly public squabble between quarterback and coach.

Blame Smith: Smith violated a major tenet of the locker-room code by blaming poor performance on an injury. An athlete isn't allowed to say that, even if it's true. Doing so had consequences with his teammates. And it is telling this season to hear so much talk about O'Sullivan's leadership.

Surgery controversy

Blame the 49ers: Though Smith suffered his shoulder injury Sept. 30 he had to hold off on surgery until December. The 49ers initially hoped that time and rehabilitation would be sufficient. (Nolan once described Smith's shoulder separation as "not very severe" for a Grade III.) Waiting so long meant that Smith still was working his arm back into shape in the spring instead of focusing solely on Martz's system.

Blame Smith: The 49ers said they were reluctant to cut into their quarterback's shoulder, an understandable sentiment considering the financial investment. Nolan said the team's medical staff believed rest was a viable option. Still, even with the delayed surgery, no one is questioning Smith's arm strength. Nolan has said he has the best arm on the team.

Rushed into action

Blame the 49ers: Nolan announced during Smith's first training camp that Tim Rattay would be the starter. Nolan abandoned that play after a 1-3 start and promoted Smith. "I like the look in Alex's eyes," he said then. The game Nolan picked for Smith's first career start was against a top-ranked Colts defense. Smith delivered four interceptions and a fumble to kick off a rookie season that included one touchdown pass and 11 interceptions.

Blame Smith: Smith took his lumps as rookie, which makes him no different from many No. 1 picks who came before him. (Peyton Manning threw 28 interceptions his first season). The point of playing time was to learn from his mistakes, but he doesn't look dramatically different today.

No mentor

Blame the 49ers: Rattay was the only semi-experienced quarterback on the roster when Smith was a rookie. The 49ers traded Rattay when Smith became the starter, leaving Ken Dorsey and Cody Pickett as the backups. Smith could have used someone to show him the ropes.

Blame Smith: The team eventually hired a mentor for Smith by signing Trent Dilfer, a Super Bowl veteran, with a reputation for helping the Seahawks' Matt Hasselbeck find a new level of play. There was no indication Dilfer had much effect on Smith.

No receivers

Blame the 49ers: Manning had Marvin Harrison. Troy Aikman had Michael Irvin. Tom Brady, who hardly needed the help, got Randy Moss. But the 49ers have yet to support their No. 1 pick with a top-flight receiver. The team hasn't had a 60-catch receiver since Terrell Owens left in 2003. Antonio Bryant and Darrell Jackson were major disappointments.

Blame Smith: The quarterback has a chance to thrive with support from Frank Gore, a dynamic running back who commands most of the defensive attention. Gore had 40.5 percent of the team's yards last year, the highest rate in the NFL, according to Stats Inc. Teams are so worried about Gore that they dare the 49ers to pass — and they still can't do it.