Attitude is exactly what companies look for when they hire people with less experience. Even for more advanced programmers in a sense it is essential because you never stop learning. This is why there is some bias towards younger people as they are supposed to be more willing to learn.
But, as with any behavior, attitude becomes less necessary if a clearly defined system for mentoring/acquiring the necessary mental models is in place. Someone who graduates from a top school and ends up working at a company where a) types mentor new hires has to try significantly less than someone who graduates from a less well known school and has to figure out some way to learn from a) types.
Btw, the way a lot of the best companies bypass the HR problem is they hire based on employee recommendations. This is another contributing factor to 'talent shortage'. There is a hiring channel at any company that is much better at recognizing potential - existing employees. The high effectiveness and limited reach of this channel adds to perceived 'talent shortage'.
