The only way we would know that is if it actually happened. All I know is that Routh wanted to be Superman and Welling didn't want to. Right now Welling is Clark and Routh is Superman, and I enjoy both of them in their respective mediums.
He only didnt want to because SV was on the air and him filming with McG would lead to SV's cancellation.
SV is coming to an end now so he may take up an offer to replace Routh if they ask him.
What Justice Bringer said was on the money... Except I think Smallville will go 8 seasons, and then end it's run.
But yes Welling said he would love to do the movie but not if it cost his friends on the show their job because the movie which McG was doing was going to have a whole new cast around Welling, and it would be the end of the show or he would have to do both at the same time, and that was just not do-able.
So Welling told McG that he would love to do the movie but only if they used the rest of the shows cast which wasn't happening.
It's called loyalty, and it's a Superman quality that Welling showed if you ask me.
Besides McG is one of the biggest hacks in the history of Hollywood... Why would ANYONE want to work with him? Oh wait wasn't McG who first brought in Routh for testing? heh yep from one hack to the next. (Singer)
Originally Welling said that he wasn't very intrested in playing SUPERBOY on tv because it had been done before, and he didn't want to do another Superboy show like the one done in the early 90's... Can't blame him that show was terrible.
But once he read the script for Smallville he was all in, and I myself saw him interview for Entertainment Tonight during season 2 of Smallville, and he was asked if he would be intrested in doing a Superman movie after the show, and he said "it would be an honor if that happened..."
I saw that with my own eyes my friend so can't nobody tell me that he didn't want to do the movie... The problem was that Singer wanted to cast a Chris Reeve look alike so he could continue the Donner/Reeve movies.
So instead of giving this generation a big screen version of THEIR Superman he went back in time, and he tried to replace Reeve, and the cast of the original movies, and he brought out an outdated, and very flawed franchise, and sugar coated it.
Those movies were good in the 70's due to the cast it had, and without that cast those movies wouldn't have worked... Case in point Superman Returns... Same universe sort of speak, and look different cast replacing Donners cast, and look at what we got!
A Total farce... Time to stop messing around with the fans, and give us a real Superman movie with a cast that looks the part! Especially the guy in the blue tights.
Routh looks like a water down version of Chris Reeve when he was playing Clark Kent at the Daily Planet but without the acting chops to back it up, and he looked down right laughable as Superman.
That is NOT what was needed for this generation...
This is why Singer fails...