Why is there no Joy in Mudville?

In the famous poem, Casey at the Bat, by Ernest L. Thayer, the final line has always given me pause.

Oh, somewhere in this favored land the sun is shining bright.
The band is playing somewhere, and somewhere hearts are light.
And, somewhere men are laughing, and little children shout,
but there is no joy in Mudville -- mighty Casey has struck out."

And just why is there no "joy in Mudville"? Did the people of fictional Mudville, even in 1888, hold one member of their hometown baseball team responsible for how they felt about themselves? This must have been quite a burden on Casey, to know he was the holder of the state of mind and happiness of all the people of his town.

I propose a more accurate, possibly a little less iambic-pentameterly correct version, of the last few lines, as follows:

Oh, somewhere in this favored land the sun is shining bright.
The band is playing somewhere, and somewhere hearts are light.
And, somewhere men are laughing, and little children shout,
But still there's joy in Mudville, even though the man struck out.

The residents of Mudville are not a silly lot,
They do not wander aimlessly seeking what is not.
'Cause long ago they found that joy was not found in a game,
But in the soul of everyman, his own joy he can claim.

As early as 1888, and probably as early as Cain and Abel, we have been taught, by society, in one form or another (usually surreptitiously and unconsciously), that the way we feel about ourselves is somehow dependent on things other than ourselves. Admittedly, the residents of Mudville were disappointed in the performance of their star player at a seemingly critical moment, buy this disappointment is a far cry from Casey's unexpected failure being the cause of draining all the joy from each member of the Mudville community.

Is the way we feel about ourselves dependent on the clothes we wear? The amount of money we make? The kind of car we drive? On someone else's (supposed) opinion of us? On some imagined circumstance over which we have no control?

We get to choose for ourselves if we have joy. We should not depend on or use any external circumstance as a measurement of how we feel inside.